Prepare v7.1.0 release (#438)

* Add hole expressions

* Fix the issue of unreported holes

* Add tests

* New line in the end of the test file

* Update CHANGELOG

* Add hole expression to the docs

* Do not treat hole as a special type

* Update docs

* Update docs/sophia_features.md

Co-authored-by: Radosław Rowicki <35342116+radrow@users.noreply.github.com>

Co-authored-by: Radosław Rowicki <35342116+radrow@users.noreply.github.com>

.circleci/config.yml

@@ -3,7 +3,7 @@ version: 2.1
 executors:
   aebuilder:
     docker:
-      - image: aeternity/builder:xenial-otp21
+      - image: aeternity/builder:bionic-otp24
         user: builder
     working_directory: ~/aesophia
 

.github/workflows/docs-develop.yml

@@ -13,10 +13,6 @@ jobs:
       - uses: actions/setup-python@v2
         with:
           python-version: 3.8
-      - uses: actions/cache@v2
-        with:
-          path: ~/.cache/pip3
-          key: ${{ runner.os }}-pip-${{ hashFiles('.github/workflows/requirements.txt') }}
       - run: pip3 install -r .github/workflows/requirements.txt -U
       - run: git config --global user.email "github-action@users.noreply.github.com"
       - run: git config --global user.name "GitHub Action"

.github/workflows/docs-release.yml

@@ -13,10 +13,6 @@ jobs:
       - uses: actions/setup-python@v2
         with:
           python-version: 3.8
-      - uses: actions/cache@v2
-        with:
-          path: ~/.cache/pip3
-          key: ${{ runner.os }}-pip-${{ hashFiles('.github/workflows/requirements.txt') }}
       - run: pip3 install -r .github/workflows/requirements.txt -U
       - run: git config --global user.email "github-action@users.noreply.github.com"
       - run: git config --global user.name "GitHub Action"

.github/workflows/requirements.txt

@@ -1,5 +1,5 @@
-mkdocs==1.2.4
-mkdocs-simple-hooks==0.1.3
-mkdocs-material==7.1.9
-mike==1.0.1
-pygments==2.11.2
+mkdocs==1.4.2
+mkdocs-simple-hooks==0.1.5
+mkdocs-material==9.0.9
+mike==1.1.2
+pygments==2.14.0

CHANGELOG.md

@@ -6,7 +6,41 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 ### Added
-- Compiler warnings for the follwing: shadowing, negative spends, division by zero, unused functions, unused includes, unused stateful annotations, unused variables, unused parameters, unused user-defined type, dead return value.
+### Changed
+### Removed
+### Fixed
+
+## [7.1.0]
+### Added
+- Options to enable/disable certain optimizations.
+- The ability to call a different instance of the current contract
+  ```
+  contract Main =
+    entrypoint spend(x : int) : int = x
+    entrypoint f(c : Main) : int = c.spend(10)
+  ```
+- Return a mapping from variables to FATE registers in the compilation output.
+- Hole expression.
+### Changed
+- Type definitions serialised to ACI as `typedefs` field instead of `type_defs` to increase compatibility.
+- Check contracts and entrypoints modifiers when implementing interfaces.
+- Contracts can no longer be used as namespaces.
+- Do not show unused stateful warning for functions that call other contracts with a non-zero value argument.
+### Fixed
+- Typechecker crashes if Chain.create or Chain.clone are used without arguments.
+
+## [7.0.1]
+### Added
+- Add CONTRIBUTING.md file.
+### Changed
+- Update Sophia syntax docs to include missing information about existing syntax.
+### Fixed
+- [404](https://github.com/aeternity/aesophia/issues/404) Contract polymorphism crashes on non-obvious child contract typing.
+
+## [7.0.0]
+### Added
+- Added support for `EXIT` opcode via `exit : (string) => 'a` function (behaves same as `ABORT`, but consumes all gas).
+- Compiler warnings for the following: shadowing, negative spends, division by zero, unused functions, unused includes, unused stateful annotations, unused variables, unused parameters, unused user-defined type, dead return value.
 - The pipe operator |>
   ```
   [1, 2, 3] |> List.first |> Option.is_some  // Option.is_some(List.first([1, 2, 3]))
@@ -16,6 +50,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   function sum(l : list(int)) : int = foldl((+), 0, l)
   function logical_and(x, y) = (&&)(x, y)
   ```
+- Contract interfaces polymorphism
 ### Changed
 - Error messages have been restructured (less newlines) to provide more unified errors. Also `pp_oneline/1` has been added.
 - Ban empty record definitions (e.g. `record r = {}` would give an error).
@@ -345,7 +380,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Simplify calldata creation - instead of passing a compiled contract, simply
   pass a (stubbed) contract string.
 
-[Unreleased]: https://github.com/aeternity/aesophia/compare/v6.1.0...HEAD
+[Unreleased]: https://github.com/aeternity/aesophia/compare/v7.1.0...HEAD
+[7.1.0]: https://github.com/aeternity/aesophia/compare/v7.0.1...v7.1.0
+[7.0.1]: https://github.com/aeternity/aesophia/compare/v7.0.0...v7.0.1
+[7.0.0]: https://github.com/aeternity/aesophia/compare/v6.1.0...v7.0.0
 [6.1.0]: https://github.com/aeternity/aesophia/compare/v6.0.2...v6.1.0
 [6.0.2]: https://github.com/aeternity/aesophia/compare/v6.0.1...v6.0.2
 [6.0.1]: https://github.com/aeternity/aesophia/compare/v6.0.0...v6.0.1

CONTRIBUTING.md

@@ -0,0 +1,40 @@
+# Contributing to Sophia
+
+## Checklist For Creating New Pull Requests
+
+The following points should be considered before creating a new PR to the Sophia compiler.
+
+### Documentation
+
+- The [Changelog](CHANGELOG.md) file should be updated for all PRs.
+- If a PR introduces a new feature that is relevant to the users of the language, the [Sophia Features Documentation](docs/sophia_features.md) should be updated to describe the new feature.
+- If a PR introduces new syntax (e.g. changes in [aeso_syntax.erl](src/aeso_syntax.erl), [aeso_scan.erl](src/aeso_scan.erl), or [aeso_parser.erl](src/aeso_parser.erl)), the [Sophia Syntax Documentation](docs/sophia_syntax.md) should be updated to include the new syntax.
+- If a PR introduces a new library, the public interface of the new library should be fully documented in the [Sophia Standard Library Documentation](docs/sophia_stdlib.md).
+- If a PR introduces a new compiler option, the new option should be documented in the file
+[aeso_compiler.md](docs/aeso_compiler.md).
+
+### Tests
+
+- If a PR introduces new syntax (e.g. changes in [aeso_syntax.erl](src/aeso_syntax.erl), [aeso_scan.erl](src/aeso_scan.erl), or [aeso_parser.erl](src/aeso_parser.erl)), the contract [all_syntax.aes](test/contracts/all_syntax.aes) should be updated to include the new syntax.
+- If a PR fixes a bug, the code that replicates the bug should be added as a new passing test contract.
+- If a PR introduces a new feature, add tests for both successful and failing usage of that feature. In order to run the entire compilation pipeline and to avoid erroring during intermediate steps, failing tests should not be mixed with the successful ones.
+
+### Source Code
+
+- If a PR introduces new syntax (e.g. changes in [aeso_syntax.erl](src/aeso_syntax.erl), [aeso_scan.erl](src/aeso_scan.erl), or [aeso_parser.erl](src/aeso_parser.erl)), the following code should be updated to handle the new syntax:
+    - The function `aeso_syntax_utils:fold/4` in the file [aeso_syntax_utils.erl](src/aeso_syntax_utils.erl).
+    - Any related pretty printing function in the file [aeso_pretty.erl](src/aeso_pretty.erl), depending on the type of the newly added syntax.
+
+## Checklist For Creating a Release
+
+- Update the version in the file [aesophia.app.src](src/aesophia.app.src).
+- Update the version in the file [rebar.config](rebar.config).
+- In the [Changelog](CHANGELOG.md):
+    - Update the `Unreleased` changes to be under the new version.
+    - Update the version at the bottom of the file.
+- Commit and the changes and create a new PR (check the commit of [v6.1.0](https://github.com/aeternity/aesophia/commit/5ad5270e381f6e810d7b8b5cdc168d283e7a90bb) for reference).
+- Create a release after merging the new PR to `master` branch.
+- After releasing `aesophia`, refer to each of the following repositories and create new releases as well, using the new `aesophia` release:
+    - [aesophia_cli](https://github.com/aeternity/aesophia_cli)
+    - [aesophia_http](https://github.com/aeternity/aesophia_http)
+    - [aerepl](https://github.com/aeternity/aerepl)

README.md

@@ -14,6 +14,7 @@ The compiler is currently being used three places
 * [Features](docs/sophia_features.md)
 * [Standard library](docs/sophia_stdlib.md)
 * [Contract examples](docs/sophia_examples.md)
+* [Contributing](CONTRIBUTING.md)
 
 Additionally you can check out the [contracts section](https://github.com/aeternity/protocol/blob/master/contracts/contracts.md) of the æternity blockchain specification.
 

docs/aeso_aci.md

@@ -67,7 +67,7 @@ generates the following JSON structure representing the contract interface:
         }
       ]
     },
-    "type_defs": [
+    "typedefs": [
       {
         "name": "answers",
         "typedef": {
@@ -138,7 +138,7 @@ be included inside another contract.
              state =>
                  #{record =>
                        [#{name => <<"a">>,type => <<"Answers.answers">>}]},
-             type_defs =>
+             typedefs =>
                  [#{name => <<"answers">>,
                     typedef => #{<<"map">> => [<<"string">>,<<"int">>]},
                     vars => []}]}}]}

docs/aeso_compiler.md

@@ -51,6 +51,36 @@ The **pp_** options all print to standard output the following:
 
 `pp_assembler` - print the generated assembler code
 
+The option `include_child_contract_symbols` includes the symbols of child contracts functions in the generated fate code. It is turned off by default to avoid making contracts bigger on chain.
+
+The option `debug_info` includes information related to debugging in the compiler output. Currently this option only includes the mapping from variables to registers.
+
+#### Options to control which compiler optimizations should run:
+
+By default all optimizations are turned on, to disable an optimization, it should be
+explicitly set to false and passed as a compiler option.
+
+List of optimizations:
+
+- optimize_inliner
+- optimize_inline_local_functions
+- optimize_bind_subexpressions
+- optimize_let_floating
+- optimize_simplifier
+- optimize_drop_unused_lets
+- optimize_push_consume
+- optimize_one_shot_var
+- optimize_write_to_dead_var
+- optimize_inline_switch_target
+- optimize_swap_push
+- optimize_swap_pop
+- optimize_swap_write
+- optimize_constant_propagation
+- optimize_prune_impossible_branches
+- optimize_single_successful_branch
+- optimize_inline_store
+- optimize_float_switch_bod
+
 #### check_call(ContractString, Options) -> CheckRet
 
 Types

docs/sophia_features.md

@@ -134,6 +134,166 @@ main contract IntHolderFactory =
 In case of a presence of child contracts (`IntHolder` in this case), the main
 contract must be pointed out with the `main` keyword as shown in the example.
 
+### Contract interfaces and polymorphism
+
+Contracts can implement one or multiple interfaces, the contract has to define
+every entrypoint from the implemented interface and the entrypoints in both
+the contract and implemented interface should have compatible types.
+
+```
+contract interface Animal =
+  entrypoint sound : () => string
+
+ contract Cat : Animal =
+  entrypoint sound() = "Cat sound"
+```
+
+Contract interfaces can extend other interfaces. An extended interface has to
+declare all entrypoints from every parent interface. All the declarations in the extended
+interface must have types compatible with the declarations from the parent
+interface.
+
+```
+contract interface II =
+  entrypoint f : () => unit
+
+contract interface I : II =
+  entrypoint f : () => unit
+  entrypoint g : () => unit
+
+contract C : I =
+  entrypoint f() = ()
+  entrypoint g() = ()
+```
+
+It is only possible to implement (or extend) an interface that has been already
+defined earlier in the file (or in an included file). Therefore recursive
+interface implementation is not allowed in Sophia.
+
+```
+// The following code would show an error
+
+contract interface X : Z =
+     entrypoint x : () => int
+
+ contract interface Y : X =
+     entrypoint x : () => int
+     entrypoint y : () => int
+
+ contract interface Z : Y =
+     entrypoint x : () => int
+     entrypoint y : () => int
+     entrypoint z : () => int
+
+ contract C : Z =
+     entrypoint x() = 1
+     entrypoint y() = 1
+     entrypoint z() = 1
+```
+
+#### Adding or removing modifiers
+
+When a `contract` or a `contract interface` implements another `contract interface`, the `payable` and `stateful` modifiers can be kept or changed, both in the contract and in the entrypoints, according to the following rules:
+
+1. A `payable` contract or interface can implement a `payable` interface or a non-`payable` interface.
+2. A non-`payable` contract or interface can only implement a non-`payable` interface, and cannot implement a `payable` interface.
+3. A `payable` entrypoint can implement a `payable` entrypoint or a non-`payable` entrypoint.
+4. A non-`payable` entrypoint can only implement a non-`payable` entrypoint, and cannot implement a `payable` entrypoint.
+5. A non-`stateful` entrypoint can implement a `stateful` entrypoint or a non-`stateful` entrypoint.
+6. A `stateful` entrypoint can only implement a `stateful` entrypoint, and cannot implement a non-`stateful` entrypoint.
+
+#### Subtyping and variance
+
+Subtyping in Sophia follows common rules that take type variance into account. As described by [Wikipedia](https://en.wikipedia.org/wiki/Covariance_and_contravariance_(computer_science)), 
+
+>Variance refers to how subtyping between more complex types relates to subtyping between their components.
+
+This concept plays an important role in complex types such as tuples, `datatype`s and functions. Depending on the context, it can apply to positions in the structure of a type, or type parameters of generic types. There are four kinds of variances:
+
+- covariant
+- contravariant
+- invariant
+- bivariant
+
+A type is said to be on a "covariant" position when it describes output or a result of some computation. Analogously, position is "contravariant" when it is an input, or a parameter. Intuitively, when a part of the type is produced by values of it, it is covariant. When it is consumed, it is contravariant. When a type appears to be simultaneously input and output, it is described as invariant. If a type is neither of those (that is, it's unused) it's bivariant. Furthermore, whenever a complex type appears on a contravariant position, all its covariant components become contravariant and vice versa.
+
+Variance influences how subtyping is applied. Types on covariant positions are subtyped normally, while contravariant the opposite way. Invariant types have to be exactly the same in order for subtyping to work. Bivariant types are always compatible.
+
+A good example of where it matters can be pictured by subtyping of function types. Let us assume there is a contract interface `Animal` and two contracts that implement it: `Dog` and `Cat`.
+
+```sophia
+contract interface Animal =
+  entrypoint age : () => int
+  
+contract Dog : Animal =
+  entrypoint age() = // ...
+  entrypoint woof() = "woof"
+  
+contract Cat : Animal =
+  entrypoint age() = // ...
+  entrypoint meow() = "meow"
+```
+
+The assumption of this exercise is that cats do not bark (because `Cat` does not define the `woof` entrypoint). If subtyping rules were applied naively, that is if we let `Dog => Dog` be a subtype of `Animal => Animal`, the following code would break:
+
+```sophia
+let f : (Dog) => string  = d => d.woof()
+let g : (Animal) => string  = f
+let c : Cat = Chain.create()
+g(c)  // Cat barking!
+```
+
+That is because arguments of functions are contravariant, as opposed to return the type which is covariant. Because of that, the assignment of `f` to `g` is invalid - while `Dog` is a subtype of `Animal`, `Dog => string` is **not** a subtype of `Animal => string`. However, `Animal => string` **is** a subtype of `Dog => string`. More than that, `(Dog => Animal) => Dog` is a subtype of `(Animal => Dog) => Animal`.
+
+This has consequences on how user-defined generic types work. A type variable gains its variance from its role in the type definition as shown in the example:
+
+```sophia
+datatype co('a) = Co('a) // co is covariant on 'a
+datatype ct('a) = Ct('a => unit) // ct is contravariant on 'a
+datatype in('a) = In('a => 'a) // in is invariant on 'a
+datatype bi('a) = Bi // bi is bivariant on 'a
+```
+
+The following facts apply here:
+
+- `co('a)` is a subtype of `co('b)` when `'a` is a subtype of `'b`
+- `ct('a)` is a subtype of `ct('b)` when `'b` is a subtype of `'a`
+- `in('a)` is a subtype of `in('b)` when `'a` is equal to `'b`
+- `bi('a)` is a subtype of `bi('b)` always
+
+That altogether induce the following rules of subtyping in Sophia:
+
+- A function type `(Args1) => Ret1` is a subtype of `(Args2) => Ret2` when `Ret1`
+is a subtype of `Ret2` and each argument type from `Args2` is a subtype of its
+counterpart in `Args1`.
+
+- A list type `list(A)` is a subtype of `list(B)` if `A` is a subtype of `B`.
+
+- An option type `option(A)` is a subtype of `option(B)` if `A` is a subtype of `B`.
+
+- A map type `map(A1, A2)` is a subtype of `map(B1, B2)` if `A1` is a subtype
+of `B1`, and `A2` is a subtype of `B2`.
+
+- An oracle type `oracle(A1, A2)` is a subtype of `oracle(B1, B2)` if `B1` is
+a subtype of `A1`, and `A2` is a subtype of `B2`.
+
+- An oracle_query type `oracle_query(A1, A2)` is a subtype of `oracle_query(B1, B2)`
+if `A1` is a subtype of `B1`, and `A2` is a subtype of `B2`.
+
+- A user-defined datatype `t(Args1)` is a subtype of `t(Args2)`
+
+- When a user-defined type `t('a)` is covariant in `'a`, then `t(A)` is a
+subtype of `t(B)` when `A` is a subtype of `B`.
+
+- When a user-defined type `t('a)` is contravariant in `'a`, then `t(A)` is a
+subtype of `t(B)` when `B` is a subtype of `A`.
+
+- When a user-defined type `t('a)` is binvariant in `'a`, then `t(A)` is a
+subtype of `t(B)` when either `A` is a subtype of `B` or when `B` is a subtype
+of `A`.
+
+- When a user-defined type `t('a)` is invariant in `'a`, then `t(A)` can never be
+a subtype of `t(B)`.
 
 ## Mutable state
 
@@ -400,6 +560,19 @@ Sophia has the following types:
 | oracle_query('a, 'b) | `oq_2oRvyowJuJnEkxy58Ckkw77XfWJrmRgmGaLzhdqb67SKEL1gPY`                                                                             |
 | contract             | `ct_Ez6MyeTMm17YnTnDdHTSrzMEBKmy7Uz2sXu347bTDPgVH2ifJ`                                                                              |
 
+## Hole expression
+
+Hole expressions, written as `???`, are expressions that are used as a placeholder. During compilation, the compiler will generate a type error indication the type of the hole expression.
+
+```
+include "List.aes"
+contract C =
+    entrypoint f() =
+        List.sum(List.map(???, [1,2,3]))
+```
+
+A hole expression found in the example above will generate the error `` Found a hole of type `(int) => int` ``. This says that the compiler expects a function from `int` to `int` in place of the `???` placeholder.
+
 ## Arithmetic
 
 Sophia integers (`int`) are represented by arbitrary-sized signed words and support the following
@@ -862,6 +1035,16 @@ function require(b : bool, err : string) =
     if(!b) abort(err)
 ```
 
+Aside from that, there is an almost equivalent function `exit`
+
+```sophia
+exit(reason : string) : 'a
+```
+
+Just like `abort`, it breaks the execution with the given reason. The difference
+however is in the gas consumption — while `abort` returns unused gas, a call to
+`exit` burns it all.
+
 ## Delegation signature
 
 Some chain operations (`Oracle.<operation>` and `AENS.<operation>`) have an

docs/sophia_stdlib.md

@@ -483,7 +483,7 @@ The address of the account that mined the current block.
 Chain.timestamp : int
 ```
 
-The timestamp of the current block.
+The timestamp of the current block (unix time, milliseconds).
 
 
 ##### difficulty

docs/sophia_syntax.md

@@ -10,8 +10,9 @@ and `*/` and can be nested.
 ### Keywords
 
 ```
-contract elif else entrypoint false function if import include let mod namespace
-private payable stateful switch true type record datatype main interface
+contract include let switch type record datatype if elif else function
+stateful payable true false mod public entrypoint private indexed namespace
+interface main using as for hiding
 ```
 
 ### Tokens
@@ -91,18 +92,30 @@ A Sophia file consists of a sequence of *declarations* in a layout block.
 ```c
 File ::= Block(TopDecl)
 
-TopDecl ::= ['payable'] 'contract' Con '=' Block(Decl)
-       | 'namespace' Con '=' Block(Decl)
-       | '@compiler' PragmaOp Version
-       | 'include' String
+TopDecl ::= ['payable'] ['main'] 'contract' Con [Implement] '=' Block(Decl)
+          | 'contract' 'interface' Con [Implement] '=' Block(Decl)
+          | 'namespace' Con '=' Block(Decl)
+          | '@compiler' PragmaOp Version
+          | 'include' String
+          | Using
+
+Implement ::= ':' Sep1(Con, ',')
 
 Decl ::= 'type'     Id ['(' TVar* ')'] '=' TypeAlias
        | 'record'   Id ['(' TVar* ')'] '=' RecordType
        | 'datatype' Id ['(' TVar* ')'] '=' DataType
        | (EModifier* 'entrypoint' | FModifier* 'function') Block(FunDecl)
+       | Using
 
 FunDecl ::= Id ':' Type                             // Type signature
           | Id Args [':' Type] '=' Block(Stmt)      // Definition
+          | Id Args [':' Type] Block(GuardedDef)    // Guarded definitions
+
+GuardedDef ::= '|' Sep1(Expr, ',') '=' Block(Stmt)
+
+Using ::= 'using' Con ['as' Con] [UsingParts]
+UsingParts ::= 'for' '[' Sep1(Id, ',') ']'
+             | 'hiding' '[' Sep1(Id, ',') ']'
 
 PragmaOp ::= '<' | '=<' | '==' | '>=' | '>'
 Version  ::= Sep1(Int, '.')
@@ -172,12 +185,17 @@ Stmt ::= 'switch' '(' Expr ')' Block(Case)
        | 'elif' '(' Expr ')' Block(Stmt)
        | 'else' Block(Stmt)
        | 'let' LetDef
+       | Using
        | Expr
 
 LetDef ::= Id Args [':' Type] '=' Block(Stmt)   // Function definition
          | Pattern '=' Block(Stmt)              // Value definition
 
 Case    ::= Pattern '=>' Block(Stmt)
+          | Pattern Block(GuardedCase)
+
+GuardedCase ::= '|' Sep1(Expr, ',') '=>' Block(Stmt)
+
 Pattern ::= Expr
 ```
 
@@ -215,10 +233,12 @@ Expr ::= '(' LamArgs ')' '=>' Block(Stmt)   // Anonymous function    (x) => x +
        | '[' Expr '..' Expr ']'             // List range            [1..n]
        | '{' Sep(FieldUpdate, ',') '}'      // Record or map value   {x = 0, y = 1}, {[key] = val}
        | '(' Expr ')'                       // Parens                (1 + 2) * 3
+       | '(' Expr '=' Expr ')'              // Assign pattern        (y = x::_)
        | Id | Con | QId | QCon              // Identifiers           x, None, Map.member, AELib.Token
        | Int | Bytes | String | Char        // Literals              123, 0xff, #00abc123, "foo", '%'
        | AccountAddress | ContractAddress   // Chain identifiers
        | OracleAddress | OracleQueryId      // Chain identifiers
+       | '???'                              // Hole expression       1 + ???
 
 Generator ::= Pattern '<-' Expr   // Generator
             | 'if' '(' Expr ')'   // Guard
@@ -244,12 +264,12 @@ UnOp  ::= '-' | '!'
 | Operators | Type
 | --- | ---
 | `-` `+` `*` `/` `mod` `^` | arithmetic operators
-| `!` `&&` `\|\|` | logical operators
+| `!` `&&` `||` | logical operators
 | `==` `!=` `<` `>` `=<` `>=` | comparison operators
 | `::` `++` | list operators
-| `\|>` | functional operators
+| `|>` | functional operators
 
-## Operator precendences
+## Operator precedence
 
 In order of highest to lowest precedence.
 
@@ -263,5 +283,5 @@ In order of highest to lowest precedence.
 | `::` `++` | right
 | `<` `>` `=<` `>=` `==` `!=` | none
 | `&&` | right
-| `\|\|` | right
-| `\|>` | left
+| `||` | right
+| `|>` | left

rebar.config

@@ -2,11 +2,10 @@
 
 {erl_opts, [debug_info]}.
 
-{deps, [ {aebytecode, {git, "https://github.com/aeternity/aebytecode.git", {ref,"0699f35"}}}
+{deps, [ {aebytecode, {git, "https://github.com/aeternity/aebytecode.git", {tag, "v3.2.0"}}}
        , {getopt, "1.0.1"}
        , {eblake2, "1.0.0"}
-       , {jsx, {git, "https://github.com/talentdeficit/jsx.git",
-                     {tag, "2.8.0"}}}
+       , {jsx, {git, "https://github.com/talentdeficit/jsx.git", {tag, "2.8.0"}}}
        ]}.
 
 {dialyzer, [
@@ -15,7 +14,7 @@
             {base_plt_apps, [erts, kernel, stdlib, crypto, mnesia]}
            ]}.
 
-{relx, [{release, {aesophia, "6.1.0"},
+{relx, [{release, {aesophia, "7.1.0"},
          [aesophia, aebytecode, getopt]},
 
         {dev_mode, true},

rebar.lock

@@ -1,11 +1,11 @@
-{"1.1.0",
+{"1.2.0",
 [{<<"aebytecode">>,
   {git,"https://github.com/aeternity/aebytecode.git",
-       {ref,"0699f35b0398bac6cd4468da654d608375bd853d"}},
+       {ref,"2a0a397afad6b45da52572170f718194018bf33c"}},
   0},
  {<<"aeserialization">>,
   {git,"https://github.com/aeternity/aeserialization.git",
-       {ref,"47aaa8f5434b365c50a35bfd1490340b19241991"}},
+       {ref,"eb68fe331bd476910394966b7f5ede7a74d37e35"}},
   1},
  {<<"base58">>,
   {git,"https://github.com/aeternity/erl-base58.git",
@@ -14,7 +14,7 @@
  {<<"eblake2">>,{pkg,<<"eblake2">>,<<"1.0.0">>},0},
  {<<"enacl">>,
   {git,"https://github.com/aeternity/enacl.git",
-       {ref,"26180f42c0b3a450905d2efd8bc7fd5fd9cece75"}},
+       {ref,"793ddb502f7fe081302e1c42227dca70b09f8e17"}},
   2},
  {<<"getopt">>,{pkg,<<"getopt">>,<<"1.0.1">>},0},
  {<<"jsx">>,
@@ -24,5 +24,8 @@
 [
 {pkg_hash,[
  {<<"eblake2">>, <<"EC8AD20E438AAB3F2E8D5D118C366A0754219195F8A0F536587440F8F9BCF2EF">>},
- {<<"getopt">>, <<"C73A9FA687B217F2FF79F68A3B637711BB1936E712B521D8CE466B29CBF7808A">>}]}
+ {<<"getopt">>, <<"C73A9FA687B217F2FF79F68A3B637711BB1936E712B521D8CE466B29CBF7808A">>}]},
+{pkg_hash_ext,[
+ {<<"eblake2">>, <<"3C4D300A91845B25D501929A26AC2E6F7157480846FAB2347A4C11AE52E08A99">>},
+ {<<"getopt">>, <<"53E1AB83B9CEB65C9672D3E7A35B8092E9BDC9B3EE80721471A161C10C59959C">>}]}
 ].

src/aeso_aci.erl

@@ -91,7 +91,7 @@ encode_contract(Contract = {Head, _, {con, _, Name}, _, _}) when ?IS_CONTRACT_HE
     {Es, Tdefs1} = lists:partition(FilterT(<<"event">>), Tdefs0),
     {Ss, Tdefs}  = lists:partition(FilterT(<<"state">>), Tdefs1),
 
-    C1 = C0#{type_defs => Tdefs},
+    C1 = C0#{typedefs => Tdefs},
 
     C2 = case Es of
              []                 -> C1;
@@ -111,7 +111,7 @@ encode_contract(Contract = {Head, _, {con, _, Name}, _, _}) when ?IS_CONTRACT_HE
 encode_contract(Namespace = {namespace, _, {con, _, Name}, _}) ->
     Tdefs = [ encode_typedef(T) || T <- sort_decls(contract_types(Namespace)) ],
     #{namespace => #{name => encode_name(Name),
-                     type_defs => Tdefs}}.
+                     typedefs => Tdefs}}.
 
 %%  Encode a function definition. Currently we are only interested in
 %%  the interface and type.
@@ -234,7 +234,7 @@ do_render_aci_json(Json) ->
 decode_contract(#{contract := #{name := Name,
                                 kind := Kind,
                                 payable := Payable,
-                                type_defs := Ts0,
+                                typedefs := Ts0,
                                 functions := Fs} = C}) ->
     MkTDef = fun(N, T) -> #{name => N, vars => [], typedef => T} end,
     Ts = [ MkTDef(<<"state">>, maps:get(state, C)) || maps:is_key(state, C) ] ++
@@ -246,7 +246,7 @@ decode_contract(#{contract := #{name := Name,
                        end,
      io_lib:format("~s", [Name])," =\n",
      decode_tdefs(Ts), decode_funcs(Fs)];
-decode_contract(#{namespace := #{name := Name, type_defs := Ts}}) when Ts /= [] ->
+decode_contract(#{namespace := #{name := Name, typedefs := Ts}}) when Ts /= [] ->
     ["namespace ", io_lib:format("~s", [Name])," =\n",
      decode_tdefs(Ts)];
 decode_contract(_) -> [].

src/aeso_ast_infer_types.erl

@@ -14,8 +14,13 @@
 
 -export([ infer/1
         , infer/2
+        , unfold_types_in_type/2
         , unfold_types_in_type/3
+        , switch_scope/2
         , pp_type/2
+        , lookup_env1/4
+        , name/1
+        , qname/1
         ]).
 
 -include("aeso_utils.hrl").
@@ -87,7 +92,11 @@
 -type byte_constraint() :: {is_bytes, utype()}
                          | {add_bytes, aeso_syntax:ann(), concat | split, utype(), utype(), utype()}.
 
--type constraint() :: named_argument_constraint() | field_constraint() | byte_constraint().
+-type aens_resolve_constraint() :: {aens_resolve_type, utype()}.
+-type oracle_type_constraint() :: {oracle_type, aeso_syntax:ann(), utype()}.
+
+-type constraint() :: named_argument_constraint() | field_constraint() | byte_constraint()
+                    | aens_resolve_constraint() | oracle_type_constraint().
 
 -record(field_info,
     { ann      :: aeso_syntax:ann()
@@ -155,6 +164,10 @@
 
 %% -- Environment manipulation -----------------------------------------------
 
+-spec switch_scope(qname(), env()) -> env().
+switch_scope(Scope, Env) ->
+    Env#env{namespace = Scope}.
+
 -spec push_scope(namespace | contract, aeso_syntax:con(), env()) -> env().
 push_scope(Kind, Con, Env) ->
     Ann  = aeso_syntax:get_ann(Con),
@@ -216,7 +229,7 @@ force_bind_fun(X, Type, Env = #env{ what = What }) ->
     NoCode = get_option(no_code, false),
     Entry = if X == "init", What == contract, not NoCode ->
                     {reserved_init, Ann, Type};
-               What == contract_interface -> {contract_fun, Ann, Type};
+               What == contract; What == contract_interface -> {contract_fun, Ann, Type};
                true -> {Ann, Type}
             end,
     on_current_scope(Env, fun(Scope = #scope{ funs = Funs }) ->
@@ -257,15 +270,24 @@ bind_state(Env) ->
         false  -> Env1
     end.
 
--spec bind_field(name(), field_info(), env()) -> env().
-bind_field(X, Info, Env = #env{ fields = Fields }) ->
+-spec bind_field_append(name(), field_info(), env()) -> env().
+bind_field_append(X, Info, Env = #env{ fields = Fields }) ->
     Fields1 = maps:update_with(X, fun(Infos) -> [Info | Infos] end, [Info], Fields),
     Env#env{ fields = Fields1 }.
 
--spec bind_fields([{name(), field_info()}], env()) -> env().
-bind_fields([], Env) -> Env;
-bind_fields([{Id, Info} | Rest], Env) ->
-    bind_fields(Rest, bind_field(Id, Info, Env)).
+-spec bind_field_update(name(), field_info(), env()) -> env().
+bind_field_update(X, Info, Env = #env{ fields = Fields }) ->
+    Fields1 = maps:update_with(X, fun([_ | Infos]) -> [Info | Infos]; ([]) -> [Info] end, [Info], Fields),
+    Env#env{ fields = Fields1 }.
+
+-spec bind_fields([{name(), field_info()}], typed | untyped, env()) -> env().
+bind_fields([], _Typing, Env) -> Env;
+bind_fields([{Id, Info} | Rest], Typing, Env) ->
+    NewEnv = case Typing of
+                 untyped -> bind_field_append(Id, Info, Env);
+                 typed   -> bind_field_update(Id, Info, Env)
+             end,
+    bind_fields(Rest, Typing, NewEnv).
 
 %% Contract entrypoints take three named arguments
 %%  gas       : int  = Call.gas_left()
@@ -283,26 +305,27 @@ contract_call_type({fun_t, Ann, [], Args, Ret}) ->
                   Named("protected", Typed({bool, Ann, false}, Id("bool")))],
      Args, {if_t, Ann, Id("protected"), {app_t, Ann, {id, Ann, "option"}, [Ret]}, Ret}}.
 
--spec bind_contract(aeso_syntax:decl(), env()) -> env().
-bind_contract({Contract, Ann, Id, _Impls, Contents}, Env)
+-spec bind_contract(typed | untyped, aeso_syntax:decl(), env()) -> env().
+bind_contract(Typing, {Contract, Ann, Id, _Impls, Contents}, Env)
   when ?IS_CONTRACT_HEAD(Contract) ->
-    Key    = name(Id),
-    Sys    = [{origin, system}],
-    Fields =
+    Key         = name(Id),
+    Sys         = [{origin, system}],
+    TypeOrFresh = fun({typed, _, _, Type}) -> Type; (_) -> fresh_uvar(Sys) end,
+    Fields      =
         [ {field_t, AnnF, Entrypoint, contract_call_type(Type)}
-          || {fun_decl, AnnF, Entrypoint, Type} <- Contents ] ++
+          || {fun_decl, AnnF, Entrypoint, Type = {fun_t, _, _, _, _}} <- Contents ] ++
         [ {field_t, AnnF, Entrypoint,
            contract_call_type(
-             {fun_t, AnnF, [], [ArgT || {typed, _, _, ArgT} <- Args], RetT})
+             {fun_t, AnnF, [], [TypeOrFresh(Arg) || Arg <- Args], TypeOrFresh(Ret)})
           }
-          || {letfun, AnnF, Entrypoint = {id, _, Name}, Args, _Type, [{guarded, _, [], {typed, _, _, RetT}}]} <- Contents,
+          || {letfun, AnnF, Entrypoint = {id, _, Name}, Args, _Type, [{guarded, _, [], Ret}]} <- Contents,
              Name =/= "init"
         ] ++
         %% Predefined fields
         [ {field_t, Sys, {id, Sys, "address"}, {id, Sys, "address"}} ] ++
         [ {field_t, Sys, {id, Sys, ?CONSTRUCTOR_MOCK_NAME},
            contract_call_type(
-             case [ [ArgT || {typed, _, _, ArgT} <- Args]
+             case [ [TypeOrFresh(Arg) || Arg <- Args]
                     || {letfun, AnnF, {id, _, "init"}, Args, _, _} <- Contents,
                        aeso_syntax:get_ann(entrypoint, AnnF, false)]
                  ++ [ Args
@@ -324,7 +347,7 @@ bind_contract({Contract, Ann, Id, _Impls, Contents}, Env)
                                             record_t = Id }}
                 || {field_t, _, {id, FieldAnn, Entrypoint}, Type} <- Fields ],
     bind_type(Key, Ann, {[], {contract_t, Fields}},
-        bind_fields(FieldInfo, Env)).
+        bind_fields(FieldInfo, Typing, Env)).
 
 %% What scopes could a given name come from?
 -spec possible_scopes(env(), qname()) -> [qname()].
@@ -399,10 +422,11 @@ lookup_env(Env, Kind, Ann, Name) ->
             end
     end.
 
--spec lookup_env1(env(), type | term, aeso_syntax:ann(), qname()) -> false | {qname(), fun_info()}.
+-spec lookup_env1(env(), type | term, aeso_syntax:ann(), qname()) -> false | {qname(), fun_info() | type_info()}.
 lookup_env1(#env{ namespace = Current, used_namespaces = UsedNamespaces, scopes = Scopes }, Kind, Ann, QName) ->
     Qual = lists:droplast(QName),
     Name = lists:last(QName),
+    QNameIsEvent = lists:suffix(["Chain", "event"], QName),
     AllowPrivate = lists:prefix(Qual, Current),
     %% Get the scope
     case maps:get(Qual, Scopes, false) of
@@ -418,6 +442,8 @@ lookup_env1(#env{ namespace = Current, used_namespaces = UsedNamespaces, scopes
                 {reserved_init, Ann1, Type} ->
                     type_error({cannot_call_init_function, Ann}),
                     {QName, {Ann1, Type}};  %% Return the type to avoid an extra not-in-scope error
+                {contract_fun, Ann1, Type} when AllowPrivate orelse QNameIsEvent ->
+                    {QName, {Ann1, Type}};
                 {contract_fun, Ann1, Type} ->
                     type_error({contract_treated_as_namespace, Ann, QName}),
                     {QName, {Ann1, Type}};
@@ -434,6 +460,9 @@ lookup_env1(#env{ namespace = Current, used_namespaces = UsedNamespaces, scopes
             end
     end.
 
+fun_arity({fun_t, _, _, Args, _}) -> length(Args);
+fun_arity(_)                      -> none.
+
 -spec lookup_record_field(env(), name()) -> [field_info()].
 lookup_record_field(Env, FieldName) ->
     maps:get(FieldName, Env#env.fields, []).
@@ -444,6 +473,11 @@ lookup_record_field(Env, FieldName, Kind) ->
     [ Fld || Fld = #field_info{ kind = K } <- lookup_record_field(Env, FieldName),
              Kind == project orelse K /= contract ].
 
+lookup_record_field_arity(Env, FieldName, Arity, Kind) ->
+    Fields = lookup_record_field(Env, FieldName, Kind),
+    [ Fld || Fld = #field_info{ field_t = FldType } <- Fields,
+             fun_arity(dereference_deep(FldType)) == Arity ].
+
 %% -- Name manipulation ------------------------------------------------------
 
 -spec qname(type_id()) -> qname().
@@ -539,8 +573,9 @@ global_env() ->
                      %% TTL constructors
                      {"RelativeTTL", Fun1(Int, TTL)},
                      {"FixedTTL",    Fun1(Int, TTL)},
-                     %% Abort
+                     %% Abort/exit
                      {"abort", Fun1(String, A)},
+                     {"exit", Fun1(String, A)},
                      {"require", Fun([Bool, String], Unit)}])
         , types = MkDefs(
                     [{"int", 0}, {"bool", 0}, {"char", 0}, {"string", 0}, {"address", 0},
@@ -823,6 +858,7 @@ infer(Contracts, Options) ->
         ets_new(type_vars, [set]),
         ets_new(warnings, [bag]),
         ets_new(type_vars_variance, [set]),
+        ets_new(functions_to_implement, [set]),
         %% Set the variance for builtin types
         ets_insert(type_vars_variance, {"list", [covariant]}),
         ets_insert(type_vars_variance, {"option", [covariant]}),
@@ -857,7 +893,7 @@ infer(Contracts, Options) ->
 -spec infer1(env(), [aeso_syntax:decl()], [aeso_syntax:decl()], list(option())) ->
     {env(), [aeso_syntax:decl()]}.
 infer1(Env, [], Acc, _Options) -> {Env, lists:reverse(Acc)};
-infer1(Env0, [{Contract, Ann, ConName, Impls, Code} | Rest], Acc, Options)
+infer1(Env0, [Contract0 = {Contract, Ann, ConName, Impls, Code} | Rest], Acc, Options)
   when ?IS_CONTRACT_HEAD(Contract) ->
     %% do type inference on each contract independently.
     Env = Env0#env{ contract_parents = maps:put(name(ConName),
@@ -873,12 +909,16 @@ infer1(Env0, [{Contract, Ann, ConName, Impls, Code} | Rest], Acc, Options)
         contract -> ets_insert(defined_contracts, {qname(ConName)});
         contract_interface -> ok
     end,
-    {Env1, Code1} = infer_contract_top(push_scope(contract, ConName, Env), What, Code, Options),
+    check_contract_preserved_payability(Env, ConName, Ann, Impls, Acc, What),
+    populate_functions_to_implement(Env, ConName, Impls, Acc),
+    Env1 = bind_contract(untyped, Contract0, Env),
+    {Env2, Code1} = infer_contract_top(push_scope(contract, ConName, Env1), What, Code, Options),
+    report_unimplemented_functions(Env1, ConName),
     Contract1 = {Contract, Ann, ConName, Impls, Code1},
-    check_implemented_interfaces(Env1, Contract1, Acc),
-    Env2 = pop_scope(Env1),
-    Env3 = bind_contract(Contract1, Env2),
-    infer1(Env3, Rest, [Contract1 | Acc], Options);
+    Env3 = pop_scope(Env2),
+    %% Rebinding because the qualifications of types are added during type inference. Could we do better?
+    Env4 = bind_contract(typed, Contract1, Env3),
+    infer1(Env4, Rest, [Contract1 | Acc], Options);
 infer1(Env, [{namespace, Ann, Name, Code} | Rest], Acc, Options) ->
     when_warning(warn_unused_includes,
                  fun() ->
@@ -895,54 +935,71 @@ infer1(Env, [{pragma, _, _} | Rest], Acc, Options) ->
     %% Pragmas are checked in check_modifiers
     infer1(Env, Rest, Acc, Options).
 
-check_implemented_interfaces(Env, {_Contract, _Ann, ConName, Impls, Code}, DefinedContracts) ->
+-spec check_contract_preserved_payability(env(), Con, Ann, Impls, Contracts, Kind) -> ok | no_return() when
+      Con :: aeso_syntax:con(),
+      Ann :: aeso_syntax:ann(),
+      Impls :: [Con],
+      Contracts :: [aeso_syntax:decl()],
+      Kind :: contract | contract_interface.
+check_contract_preserved_payability(Env, ContractName, ContractAnn, Impls, DefinedContracts, Kind) ->
+    Payable = proplists:get_value(payable, ContractAnn, false),
+    ImplsNames = [ name(I) || I <- Impls ],
+    Interfaces = [ Con || I = {contract_interface, _, Con, _, _} <- DefinedContracts,
+                          lists:member(name(Con), ImplsNames),
+                          aeso_syntax:get_ann(payable, I, false) ],
+
     create_type_errors(),
-    AllInterfaces = [{name(IName), I} || I = {contract_interface, _, IName, _, _} <- DefinedContracts],
-    ImplsNames = lists:map(fun name/1, Impls),
+    [ type_error({unpreserved_payablity, Kind, ContractName, I}) || I <- Interfaces, Payable == false ],
+    destroy_and_report_type_errors(Env),
 
-    %% All implemented intrefaces should already be defined
-    lists:foreach(fun(Impl) -> case proplists:get_value(name(Impl), AllInterfaces) of
-                                   undefined -> type_error({referencing_undefined_interface, Impl});
-                                   _         -> ok
-                               end
-                  end, Impls),
+    ok.
 
-    ImplementedInterfaces = [I || I <- [proplists:get_value(Name, AllInterfaces) || Name <- ImplsNames],
-                                    I /= undefined],
-    Funs = [ Fun || Fun <- Code,
-                    element(1, Fun) == letfun orelse element(1, Fun) == fun_decl ],
-    check_implemented_interfaces1(Env, ImplementedInterfaces, ConName, Funs, AllInterfaces),
+%% Report all functions that were not implemented by the contract ContractName.
+-spec report_unimplemented_functions(env(), ContractName) -> ok | no_return() when
+      ContractName :: aeso_syntax:con().
+report_unimplemented_functions(Env, ContractName) ->
+    create_type_errors(),
+    [ type_error({unimplemented_interface_function, ContractName, name(I), FunName})
+      || {FunName, I, _} <- ets_tab2list(functions_to_implement) ],
     destroy_and_report_type_errors(Env).
 
-%% Recursively check that all directly and indirectly referenced interfaces are implemented
-check_implemented_interfaces1(_, [], _, _, _) ->
-    ok;
-check_implemented_interfaces1(Env, [{contract_interface, _, IName, _, Decls} | Interfaces],
-                              ConId, Impls, AllInterfaces) ->
-    Unmatched = match_impls(Env, Decls, ConId, name(IName), Impls),
-    check_implemented_interfaces1(Env, Interfaces, ConId, Unmatched, AllInterfaces).
+%% Return a list of all function declarations to be implemented, given the list
+%% of interfaces to be implemented Impls and all the previously defined
+%% contracts DefinedContracts>
+-spec functions_to_implement(Impls, DefinedContracts) -> [{InterfaceCon, FunDecl}] when
+      Impls :: [aeso_syntax:con()],
+      DefinedContracts :: [aeso_syntax:decl()],
+      InterfaceCon :: aeso_syntax:con(),
+      FunDecl :: aeso_syntax:fundecl().
+functions_to_implement(Impls, DefinedContracts) ->
+    ImplsNames = [ name(I) || I <- Impls ],
+    Interfaces = [ I || I = {contract_interface, _, Con, _, _} <- DefinedContracts,
+                        lists:member(name(Con), ImplsNames) ],
 
-%% Match the functions of the contract with the interfaces functions, and return unmatched functions
-match_impls(_, [], _, _, Impls) ->
-    Impls;
-match_impls(Env, [{fun_decl, _, {id, _, FunName}, FunType = {fun_t, _, _, ArgsTypes, RetDecl}} | Decls], ConId, IName, Impls) ->
-    Match = fun({letfun, _, {id, _, FName}, Args, RetFun, _}) when FName == FunName ->
-                    length(ArgsTypes) == length(Args) andalso
-                    unify(Env#env{unify_throws = false}, RetDecl, RetFun, unknown) andalso
-                    lists:all(fun({T1, {typed, _, _, T2}}) -> unify(Env#env{unify_throws = false}, T1, T2, unknown) end,
-                              lists:zip(ArgsTypes, Args));
-               ({fun_decl, _, {id, _, FName}, FunT}) when FName == FunName ->
-                    unify(Env#env{unify_throws = false}, FunT, FunType, unknown);
-               (_) -> false
-            end,
-    UnmatchedImpls = case lists:search(Match, Impls) of
-                         {value, V} ->
-                             lists:delete(V, Impls);
-                         false ->
-                             type_error({unimplemented_interface_function, ConId, IName, FunName}),
-                             Impls
-                     end,
-    match_impls(Env, Decls, ConId, IName, UnmatchedImpls).
+    %% All implemented intrefaces should already be defined
+    InterfacesNames = [name(element(3, I)) || I <- Interfaces],
+    [ begin
+        Found = lists:member(name(Impl), InterfacesNames),
+        Found orelse type_error({referencing_undefined_interface, Impl})
+      end || Impl <- Impls
+    ],
+
+    lists:flatten([ [ {Con, Decl} || Decl <- Decls] || {contract_interface, _, Con, _, Decls} <- Interfaces ]).
+
+%% Fill the ets table functions_to_implement with functions from the implemented
+%% interfaces Impls.
+-spec populate_functions_to_implement(env(), ContractName, Impls, DefinedContracts) -> ok | no_return() when
+      ContractName :: aeso_syntax:con(),
+      Impls :: [aeso_syntax:con()],
+      DefinedContracts :: [aeso_syntax:decl()].
+populate_functions_to_implement(Env, ContractName, Impls, DefinedContracts) ->
+    create_type_errors(),
+    [ begin
+        Inserted = ets_insert_new(functions_to_implement, {name(Id), I, Decl}),
+        [{_, I2, _}] = ets_lookup(functions_to_implement, name(Id)),
+        Inserted orelse type_error({interface_implementation_conflict, ContractName, I, I2, Id})
+      end || {I, Decl = {fun_decl, _, Id, _}} <- functions_to_implement(Impls, DefinedContracts) ],
+    destroy_and_report_type_errors(Env).
 
 %% Asserts that the main contract is somehow defined.
 identify_main_contract(Contracts, Options) ->
@@ -1013,6 +1070,9 @@ infer_contract(Env0, What, Defs0, Options) ->
             contract           -> bind_state(Env1)   %% bind state and put
         end,
     {ProtoSigs, Decls} = lists:unzip([ check_fundecl(Env1, Decl) || Decl <- Get(prototype, Defs) ]),
+    [ type_error({missing_definition, Id}) || {fun_decl, _, Id, _} <- Decls,
+                                              What =:= contract,
+                                              get_option(no_code, false) =:= false ],
     Env3      = bind_funs(ProtoSigs, Env2),
     Functions = Get(function, Defs),
     %% Check for duplicates in Functions (we turn it into a map below)
@@ -1027,8 +1087,10 @@ infer_contract(Env0, What, Defs0, Options) ->
     {Env4, Defs1} = check_sccs(Env3, FunMap, SCCs, []),
     %% Remove namespaces used in the current namespace
     Env5 = Env4#env{ used_namespaces = OldUsedNamespaces },
-    %% Check that `init` doesn't read or write the state
-    check_state_dependencies(Env4, Defs1),
+    %% Check that `init` doesn't read or write the state and that `init` is not missing
+    check_state(Env4, Defs1),
+    %% Check that entrypoints have first-order arg types and return types
+    check_entrypoints(Defs1),
     destroy_and_report_type_errors(Env4),
     %% Add inferred types of definitions
     {Env5, TypeDefs ++ Decls ++ Defs1}.
@@ -1095,6 +1157,7 @@ check_typedef_sccs(Env, TypeMap, [{acyclic, Name} | SCCs], Acc) ->
     case maps:get(Name, TypeMap, undefined) of
         undefined -> check_typedef_sccs(Env, TypeMap, SCCs, Acc);    %% Builtin type
         {type_def, Ann, D, Xs, Def0} ->
+            check_parameterizable(D, Xs),
             Def  = check_event(Env, Name, Ann, check_typedef(bind_tvars(Xs, Env), Def0)),
             Acc1 = [{type_def, Ann, D, Xs, Def} | Acc],
             Env1 = bind_type(Name, Ann, {Xs, Def}, Env),
@@ -1194,6 +1257,10 @@ check_usings(Env = #env{ used_namespaces = UsedNamespaces }, [{using, Ann, Con,
             create_type_errors(),
             type_error({using_undefined_namespace, Ann, qname(Con)}),
             destroy_and_report_type_errors(Env);
+        #scope{kind = contract} ->
+            create_type_errors(),
+            type_error({using_undefined_namespace, Ann, qname(Con)}),
+            destroy_and_report_type_errors(Env);
         Scope ->
             Nsp = case Parts of
                       none ->
@@ -1347,9 +1414,16 @@ check_named_arg(Env, {named_arg_t, Ann, Id, Type, Default}) ->
 -spec check_fields(env(), #{ name() => aeso_syntax:decl() }, type(), [aeso_syntax:field_t()]) -> env().
 check_fields(Env, _TypeMap, _, []) -> Env;
 check_fields(Env, TypeMap, RecTy, [{field_t, Ann, Id, Type} | Fields]) ->
-    Env1 = bind_field(name(Id), #field_info{ ann = Ann, kind = record, field_t = Type, record_t = RecTy }, Env),
+    Env1 = bind_field_append(name(Id), #field_info{ ann = Ann, kind = record, field_t = Type, record_t = RecTy }, Env),
     check_fields(Env1, TypeMap, RecTy, Fields).
 
+check_parameterizable({id, Ann, "event"}, [_ | _]) ->
+    type_error({parameterized_event, Ann});
+check_parameterizable({id, Ann, "state"}, [_ | _]) ->
+    type_error({parameterized_state, Ann});
+check_parameterizable(_Name, _Xs) ->
+    ok.
+
 check_event(Env, "event", Ann, Def) ->
     case Def of
         {variant_t, Cons} ->
@@ -1439,15 +1513,50 @@ check_reserved_entrypoints(Funs) ->
 -spec check_fundecl(env(), aeso_syntax:decl()) -> {{name(), typesig()}, aeso_syntax:decl()}.
 check_fundecl(Env, {fun_decl, Ann, Id = {id, _, Name}, Type = {fun_t, _, _, _, _}}) ->
     Type1 = {fun_t, _, Named, Args, Ret} = check_type(Env, Type),
-    {{Name, {type_sig, Ann, none, Named, Args, Ret}}, {fun_decl, Ann, Id, Type1}};
+    TypeSig = {type_sig, Ann, none, Named, Args, Ret},
+    register_implementation(Id, TypeSig),
+    {{Name, TypeSig}, {fun_decl, Ann, Id, Type1}};
 check_fundecl(Env, {fun_decl, Ann, Id = {id, _, Name}, Type}) ->
     type_error({fundecl_must_have_funtype, Ann, Id, Type}),
     {{Name, {type_sig, Ann, none, [], [], Type}}, check_type(Env, Type)}.
 
+%% Register the function FunId as implemented by deleting it from the functions
+%% to be implemented table if it is included there, or return true otherwise.
+-spec register_implementation(FunId, FunSig) -> true | no_return() when
+      FunId :: aeso_syntax:id(),
+      FunSig :: typesig().
+register_implementation(Id, Sig) ->
+    Name = name(Id),
+    case ets_lookup(functions_to_implement, Name) of
+        [{Name, Interface, Decl = {fun_decl, _, DeclId, _}}] ->
+            DeclStateful   = aeso_syntax:get_ann(stateful,   Decl, false),
+            DeclPayable    = aeso_syntax:get_ann(payable,    Decl, false),
+
+            SigEntrypoint = aeso_syntax:get_ann(entrypoint, Sig, false),
+            SigStateful   = aeso_syntax:get_ann(stateful,   Sig, false),
+            SigPayable    = aeso_syntax:get_ann(payable,    Sig, false),
+
+            [ type_error({function_should_be_entrypoint, Id, DeclId, Interface})
+                || not SigEntrypoint ],
+
+            [ type_error({entrypoint_cannot_be_stateful, Id, DeclId, Interface})
+                || SigStateful andalso not DeclStateful ],
+
+            [ type_error({entrypoint_must_be_payable, Id, DeclId, Interface})
+                || not SigPayable andalso DeclPayable ],
+
+            ets_delete(functions_to_implement, Name);
+        [] ->
+            true;
+        _ ->
+            error("Ets set has multiple keys")
+    end.
+
 infer_nonrec(Env, LetFun) ->
     create_constraints(),
-    NewLetFun = infer_letfun(Env, LetFun),
+    NewLetFun = {{_, Sig}, _} = infer_letfun(Env, LetFun),
     check_special_funs(Env, NewLetFun),
+    register_implementation(get_letfun_id(LetFun), Sig),
     solve_then_destroy_and_report_unsolved_constraints(Env),
     Result = {TypeSig, _} = instantiate(NewLetFun),
     print_typesig(TypeSig),
@@ -1476,7 +1585,8 @@ infer_letrec(Env, Defs) ->
     ExtendEnv = bind_funs(Funs, Env),
     Inferred =
         [ begin
-            Res    = {{Name, TypeSig}, _} = infer_letfun(ExtendEnv, LF),
+            Res    = {{Name, TypeSig}, LetFun} = infer_letfun(ExtendEnv, LF),
+            register_implementation(get_letfun_id(LetFun), TypeSig),
             Got    = proplists:get_value(Name, Funs),
             Expect = typesig_to_fun_t(TypeSig),
             unify(Env, Got, Expect, {check_typesig, Name, Got, Expect}),
@@ -1528,6 +1638,9 @@ infer_letfun1(Env0 = #env{ namespace = NS }, {letfun, Attrib, Fun = {id, NameAtt
     {{Name, TypeSig},
      {letfun, Attrib, {id, NameAttrib, Name}, TypedArgs, ResultType, NewGuardedBodies}}.
 
+get_letfun_id({fun_clauses, _, Id, _, _}) -> Id;
+get_letfun_id({letfun, _, Id, _, _, _})   -> Id.
+
 desugar_clauses(Ann, Fun, {type_sig, _, _, _, ArgTypes, RetType}, Clauses) ->
     NeedDesugar =
         case Clauses of
@@ -1568,13 +1681,13 @@ app_t(Ann, Name, Args) -> {app_t, Ann, Name, Args}.
 lookup_name(Env, As, Name) ->
     lookup_name(Env, As, Name, []).
 
-lookup_name(Env = #env{ namespace = NS, current_function = {id, _, Fun} = CurFn }, As, Id, Options) ->
+lookup_name(Env = #env{ namespace = NS, current_function = CurFn }, As, Id, Options) ->
     case lookup_env(Env, term, As, qname(Id)) of
         false ->
             type_error({unbound_variable, Id}),
             {Id, fresh_uvar(As)};
         {QId, {_, Ty}} ->
-            when_warning(warn_unused_variables, fun() -> used_variable(NS, Fun, QId) end),
+            when_warning(warn_unused_variables, fun() -> used_variable(NS, name(CurFn), QId) end),
             when_warning(warn_unused_functions,
                          fun() -> register_function_call(NS ++ qname(CurFn), QId) end),
             Freshen = proplists:get_value(freshen, Options, false),
@@ -1605,15 +1718,63 @@ check_stateful(#env { current_function = Fun }, _Id, _Type) ->
 
 %% Hack: don't allow passing the 'value' named arg if not stateful. This only
 %% works since the user can't create functions with named arguments.
-check_stateful_named_arg(#env{ stateful = false, current_function = Fun }, {id, _, "value"}, Default) ->
+check_stateful_named_arg(#env{ stateful = Stateful, current_function = Fun }, {id, _, "value"}, Default) ->
     case Default of
         {int, _, 0} -> ok;
-        _           -> type_error({value_arg_not_allowed, Default, Fun})
+        _           ->
+            case Stateful of
+                true  -> when_warning(warn_unused_stateful, fun() -> used_stateful(Fun) end);
+                false -> type_error({value_arg_not_allowed, Default, Fun})
+            end
     end;
 check_stateful_named_arg(_, _, _) -> ok.
 
-%% Check that `init` doesn't read or write the state
-check_state_dependencies(Env, Defs) ->
+check_entrypoints(Defs) ->
+    [ ensure_first_order_entrypoint(LetFun)
+      || LetFun <- Defs,
+         aeso_syntax:get_ann(entrypoint, LetFun, false),
+         get_option(allow_higher_order_entrypoints, false) =:= false ].
+
+ensure_first_order_entrypoint({letfun, Ann, Id = {id, _, Name}, Args, Ret, _}) ->
+    [ ensure_first_order(ArgType, {higher_order_entrypoint, AnnArg, Id, {argument, ArgId, ArgType}})
+      || {typed, AnnArg, ArgId, ArgType} <- Args ],
+    [ ensure_first_order(Ret, {higher_order_entrypoint, Ann, Id, {result, Ret}})
+      || Name /= "init" ],  %% init can return higher-order values, since they're written to the store
+                            %% rather than being returned.
+    ok.
+
+ensure_first_order(Type, Err) ->
+    is_first_order(Type) orelse type_error(Err).
+
+is_first_order({fun_t, _, _, _, _})    -> false;
+is_first_order(Ts) when is_list(Ts)    -> lists:all(fun is_first_order/1, Ts);
+is_first_order(Tup) when is_tuple(Tup) -> is_first_order(tuple_to_list(Tup));
+is_first_order(_)                      -> true.
+
+ensure_monomorphic(Type, Err) ->
+    is_monomorphic(Type) orelse type_error(Err).
+
+is_monomorphic({tvar, _, _})           -> false;
+is_monomorphic(Ts) when is_list(Ts)    -> lists:all(fun is_monomorphic/1, Ts);
+is_monomorphic(Tup) when is_tuple(Tup) -> is_monomorphic(tuple_to_list(Tup));
+is_monomorphic(_)                      -> true.
+
+check_state_init(Env) ->
+    Top = Env#env.namespace,
+    StateType = lookup_type(Env, {id, [{origin, system}], "state"}),
+    case unfold_types_in_type(Env, StateType) of
+        false  ->
+            ok;
+        {_, {_, {_, {alias_t, {tuple_t, _, []}}}}} ->  %% type state = ()
+            ok;
+        _ ->
+            #scope{ ann = AnnCon } = get_scope(Env, Top),
+            type_error({missing_init_function, {con, AnnCon, lists:last(Top)}})
+    end.
+
+%% Check that `init` doesn't read or write the state and that `init` is defined
+%% when the state type is not unit
+check_state(Env, Defs) ->
     Top       = Env#env.namespace,
     GetState  = Top ++ ["state"],
     SetState  = Top ++ ["put"],
@@ -1622,7 +1783,7 @@ check_state_dependencies(Env, Defs) ->
     Funs      = [ {Top ++ [Name], Fun} || Fun = {letfun, _, {id, _, Name}, _Args, _Type, _GuardedBodies} <- Defs ],
     Deps      = maps:from_list([{Name, UsedNames(Def)} || {Name, Def} <- Funs]),
     case maps:get(Init, Deps, false) of
-        false -> ok;    %% No init, so nothing to check
+        false -> get_option(no_code, false) orelse check_state_init(Env);
         _     ->
             [ type_error({init_depends_on_state, state, Chain})
               || Chain <- get_call_chains(Deps, Init, GetState) ],
@@ -1682,6 +1843,10 @@ infer_expr(_Env, Body={contract_pubkey, As, _}) ->
     {typed, As, Body, Con};
 infer_expr(_Env, Body={id, As, "_"}) ->
     {typed, As, Body, fresh_uvar(As)};
+infer_expr(_Env, Body={id, As, "???"}) ->
+    T = fresh_uvar(As),
+    type_error({hole_found, As, T}),
+    {typed, As, Body, T};
 infer_expr(Env, Id = {Tag, As, _}) when Tag == id; Tag == qid ->
     {QName, Type} = lookup_name(Env, As, Id),
     {typed, As, QName, Type};
@@ -1764,12 +1929,17 @@ infer_expr(Env, {app, Ann, Fun, Args0} = App) ->
             NewFun0 = infer_expr(Env, Fun),
             NewArgs = [infer_expr(Env, A) || A <- Args],
             ArgTypes = [T || {typed, _, _, T} <- NewArgs],
-            NewFun1 = {typed, _, _, FunType} = infer_var_args_fun(Env, NewFun0, NamedArgs1, ArgTypes),
+            NewFun1 = {typed, _, FunName, FunType} = infer_var_args_fun(Env, NewFun0, NamedArgs1, ArgTypes),
             When = {infer_app, Fun, NamedArgs1, Args, FunType, ArgTypes},
             GeneralResultType = fresh_uvar(Ann),
             ResultType = fresh_uvar(Ann),
             unify(Env, FunType, {fun_t, [], NamedArgsVar, ArgTypes, GeneralResultType}, When),
             when_warning(warn_negative_spend, fun() -> warn_potential_negative_spend(Ann, NewFun1, NewArgs) end),
+            [ add_constraint({aens_resolve_type, GeneralResultType})
+              || element(3, FunName) =:= ["AENS", "resolve"] ],
+            [ add_constraint({oracle_type, Ann, OType})
+              || OType <- [get_oracle_type(FunName, ArgTypes, GeneralResultType)],
+                 OType =/= false ],
             add_constraint(
               #dependent_type_constraint{ named_args_t = NamedArgsVar,
                                           named_args   = NamedArgs1,
@@ -2128,7 +2298,7 @@ next_count() ->
 ets_tables() ->
     [options, type_vars, constraints, freshen_tvars, type_errors,
      defined_contracts, warnings, function_calls, all_functions,
-     type_vars_variance].
+     type_vars_variance, functions_to_implement].
 
 clean_up_ets() ->
     [ catch ets_delete(Tab) || Tab <- ets_tables() ],
@@ -2164,10 +2334,18 @@ ets_delete(Name) ->
     put(aeso_ast_infer_types, maps:remove(Name, Tabs)),
     ets:delete(TabId).
 
+ets_delete(Name, Key) ->
+    TabId = ets_tabid(Name),
+    ets:delete(TabId, Key).
+
 ets_insert(Name, Object) ->
     TabId = ets_tabid(Name),
     ets:insert(TabId, Object).
 
+ets_insert_new(Name, Object) ->
+    TabId = ets_tabid(Name),
+    ets:insert_new(TabId, Object).
+
 ets_lookup(Name, Key) ->
     TabId = ets_tabid(Name),
     ets:lookup(TabId, Key).
@@ -2234,7 +2412,12 @@ solve_constraints(Env) ->
                field_t  = FieldType,
                kind     = Kind,
                context  = When }) ->
-                case lookup_record_field(Env, FieldName, Kind) of
+                Arity = fun_arity(dereference_deep(FieldType)),
+                FieldInfos = case Arity of
+                                 none -> lookup_record_field(Env, FieldName, Kind);
+                                 _    -> lookup_record_field_arity(Env, FieldName, Arity, Kind)
+                             end,
+                case FieldInfos of
                     [] ->
                         type_error({undefined_field, Field}),
                         false;
@@ -2290,11 +2473,19 @@ destroy_and_report_unsolved_constraints(Env) ->
                            (#named_argument_constraint{}) -> true;
                            (_)                            -> false
                         end, OtherCs2),
-    {BytesCs, []} =
+    {BytesCs, OtherCs4} =
         lists:partition(fun({is_bytes, _})              -> true;
                            ({add_bytes, _, _, _, _, _}) -> true;
                            (_)                          -> false
                         end, OtherCs3),
+    {AensResolveCs, OtherCs5} =
+        lists:partition(fun({aens_resolve_type, _}) -> true;
+                           (_)                      -> false
+                        end, OtherCs4),
+    {OracleTypeCs, []} =
+        lists:partition(fun({oracle_type, _, _}) -> true;
+                           (_)                   -> false
+                        end, OtherCs5),
 
     Unsolved = [ S || S <- [ solve_constraint(Env, dereference_deep(C)) || C <- NamedArgCs ],
                       S == unsolved ],
@@ -2312,9 +2503,20 @@ destroy_and_report_unsolved_constraints(Env) ->
     check_record_create_constraints(Env, CreateCs),
     check_is_contract_constraints(Env, ContractCs),
     check_bytes_constraints(Env, BytesCs),
+    check_aens_resolve_constraints(Env, AensResolveCs),
+    check_oracle_type_constraints(Env, OracleTypeCs),
 
     destroy_constraints().
 
+get_oracle_type({qid, _, ["Oracle", "register"]},      _        , OType) -> OType;
+get_oracle_type({qid, _, ["Oracle", "query"]},        [OType| _], _    ) -> OType;
+get_oracle_type({qid, _, ["Oracle", "get_question"]}, [OType| _], _    ) -> OType;
+get_oracle_type({qid, _, ["Oracle", "get_answer"]},   [OType| _], _    ) -> OType;
+get_oracle_type({qid, _, ["Oracle", "check"]},        [OType| _], _    ) -> OType;
+get_oracle_type({qid, _, ["Oracle", "check_query"]},  [OType| _], _    ) -> OType;
+get_oracle_type({qid, _, ["Oracle", "respond"]},      [OType| _], _    ) -> OType;
+get_oracle_type(_Fun, _Args, _Ret) -> false.
+
 %% -- Named argument constraints --
 
 %% If false, a type error has been emitted, so it's safe to drop the constraint.
@@ -2441,6 +2643,32 @@ check_bytes_constraint(Env, {add_bytes, Ann, Fun, A0, B0, C0}) ->
         _ -> type_error({unsolved_bytes_constraint, Ann, Fun, A, B, C})
     end.
 
+check_aens_resolve_constraints(_Env, []) ->
+    ok;
+check_aens_resolve_constraints(Env, [{aens_resolve_type, Type} | Rest]) ->
+    Type1 = unfold_types_in_type(Env, instantiate(Type)),
+    {app_t, _, {id, _, "option"}, [Type2]} = Type1,
+    case Type2 of
+        {id, _, "string"} -> ok;
+        {id, _, "address"} -> ok;
+        {con, _, _} -> ok;
+        {app_t, _, {id, _, "oracle"}, [_, _]} -> ok;
+        {app_t, _, {id, _, "oracle_query"}, [_, _]} -> ok;
+        _ -> type_error({invalid_aens_resolve_type, aeso_syntax:get_ann(Type), Type2})
+    end,
+    check_aens_resolve_constraints(Env, Rest).
+
+check_oracle_type_constraints(_Env, []) ->
+    ok;
+check_oracle_type_constraints(Env, [{oracle_type, Ann, OType} | Rest]) ->
+    Type = unfold_types_in_type(Env, instantiate(OType)),
+    {app_t, _, {id, _, "oracle"}, [QType, RType]} = Type,
+    ensure_monomorphic(QType, {invalid_oracle_type, polymorphic,  query,    Ann, Type}),
+    ensure_monomorphic(RType, {invalid_oracle_type, polymorphic,  response, Ann, Type}),
+    ensure_first_order(QType, {invalid_oracle_type, higher_order, query,    Ann, Type}),
+    ensure_first_order(RType, {invalid_oracle_type, higher_order, response, Ann, Type}),
+    check_oracle_type_constraints(Env, Rest).
+
 %% -- Field constraints --
 
 check_record_create_constraints(_, []) -> ok;
@@ -2684,6 +2912,8 @@ unify0(Env, A, B, Variance, When) ->
 
 unify1(_Env, {uvar, _, R}, {uvar, _, R}, _Variance, _When) ->
     true;
+unify1(_Env, {uvar, _, _}, {fun_t, _, _, var_args, _}, _Variance, When) ->
+    type_error({unify_varargs, When});
 unify1(Env, {uvar, A, R}, T, _Variance, When) ->
     case occurs_check(R, T) of
         true ->
@@ -2707,6 +2937,12 @@ unify1(Env, [A|B], [C|D], Variance, When) ->
     unify0(Env, A, C, Variance, When) andalso unify0(Env, B, D, Variance, When);
 unify1(_Env, X, X, _Variance, _When) ->
     true;
+unify1(_Env, _A, {id, _, "void"}, Variance, _When)
+  when Variance == covariant orelse Variance == bivariant ->
+    true;
+unify1(_Env, {id, _, "void"}, _B, Variance, _When)
+  when Variance == contravariant orelse Variance == bivariant ->
+    true;
 unify1(_Env, {id, _, Name}, {id, _, Name}, _Variance, _When) ->
     true;
 unify1(Env, A = {con, _, NameA}, B = {con, _, NameB}, Variance, When) ->
@@ -3164,6 +3400,9 @@ mk_error({cannot_unify, A, B, Cxt, When}) ->
                         [pp(instantiate(A)), pp(instantiate(B))]),
     {Pos, Ctxt} = pp_when(When),
     mk_t_err(Pos, Msg, Ctxt);
+mk_error({hole_found, Ann, Type}) ->
+    Msg = io_lib:format("Found a hole of type `~s`", [pp(instantiate(Type))]),
+    mk_t_err(pos(Ann), Msg);
 mk_error({unbound_variable, Id}) ->
     Msg = io_lib:format("Unbound variable `~s`", [pp(Id)]),
     case Id of
@@ -3447,7 +3686,7 @@ mk_error({multiple_main_contracts, Ann}) ->
     Msg = "Only one main contract can be defined.",
     mk_t_err(pos(Ann), Msg);
 mk_error({unify_varargs, When}) ->
-    Msg = "Cannot unify variable argument list.",
+    Msg = "Cannot infer types for variable argument list.",
     {Pos, Ctxt} = pp_when(When),
     mk_t_err(Pos, Msg, Ctxt);
 mk_error({clone_no_contract, Ann}) ->
@@ -3479,11 +3718,77 @@ mk_error({empty_record_definition, Ann, Name}) ->
     Msg = io_lib:format("Empty record definitions are not allowed. Cannot define the record `~s`", [Name]),
     mk_t_err(pos(Ann), Msg);
 mk_error({unimplemented_interface_function, ConId, InterfaceName, FunName}) ->
-    Msg = io_lib:format("Unimplemented function `~s` from the interface `~s` in the contract `~s`", [FunName, InterfaceName, pp(ConId)]),
+    Msg = io_lib:format("Unimplemented entrypoint `~s` from the interface `~s` in the contract `~s`", [FunName, InterfaceName, pp(ConId)]),
     mk_t_err(pos(ConId), Msg);
 mk_error({referencing_undefined_interface, InterfaceId}) ->
     Msg = io_lib:format("Trying to implement or extend an undefined interface `~s`", [pp(InterfaceId)]),
     mk_t_err(pos(InterfaceId), Msg);
+mk_error({missing_definition, Id}) ->
+    Msg = io_lib:format("Missing definition of function `~s`", [name(Id)]),
+    mk_t_err(pos(Id), Msg);
+mk_error({parameterized_state, Ann}) ->
+    Msg = "The state type cannot be parameterized",
+    mk_t_err(pos(Ann), Msg);
+mk_error({parameterized_event, Ann}) ->
+    Msg = "The event type cannot be parameterized",
+    mk_t_err(pos(Ann), Msg);
+mk_error({missing_init_function, Con}) ->
+    Msg = io_lib:format("Missing `init` function for the contract `~s`.", [name(Con)]),
+    Cxt = "The `init` function can only be omitted if the state type is `unit`",
+    mk_t_err(pos(Con), Msg, Cxt);
+mk_error({higher_order_entrypoint, Ann, {id, _, Name}, Thing}) ->
+    What = "higher-order (contains function types)",
+    ThingS = case Thing of
+                 {argument, X, T} -> io_lib:format("argument\n~s`\n", [pp_typed("  `", X, T)]);
+                 {result, T}      -> io_lib:format("return type\n~s`\n", [pp_type("  `", T)])
+             end,
+    Bad = case Thing of
+              {argument, _, _} -> io_lib:format("has a ~s type", [What]);
+              {result, _}      -> io_lib:format("is ~s", [What])
+          end,
+    Msg = io_lib:format("The ~sof entrypoint `~s` ~s",
+                        [ThingS, Name, Bad]),
+    mk_t_err(pos(Ann), Msg);
+mk_error({invalid_aens_resolve_type, Ann, T}) ->
+    Msg = io_lib:format("Invalid return type of `AENS.resolve`:\n"
+                        "~s`\n"
+                        "It must be a `string` or a pubkey type (`address`, `oracle`, etc)",
+                        [pp_type("  `", T)]),
+    mk_t_err(pos(Ann), Msg);
+mk_error({invalid_oracle_type, Why, What, Ann, Type}) ->
+    WhyS = case Why of higher_order -> "higher-order (contain function types)";
+                       polymorphic  -> "polymorphic (contain type variables)" end,
+    Msg = io_lib:format("Invalid oracle type\n~s`", [pp_type("  `", Type)]),
+    Cxt = io_lib:format("The ~s type must not be ~s", [What, WhyS]),
+    mk_t_err(pos(Ann), Msg, Cxt);
+mk_error({interface_implementation_conflict, Contract, I1, I2, Fun}) ->
+    Msg = io_lib:format("Both interfaces `~s` and `~s` implemented by "
+                        "the contract `~s` have a function called `~s`",
+                        [name(I1), name(I2), name(Contract), name(Fun)]),
+    mk_t_err(pos(Contract), Msg);
+mk_error({function_should_be_entrypoint, Impl, Base, Interface}) ->
+    Msg = io_lib:format("`~s` must be declared as an entrypoint instead of a function "
+                        "in order to implement the entrypoint `~s` from the interface `~s`",
+                        [name(Impl), name(Base), name(Interface)]),
+    mk_t_err(pos(Impl), Msg);
+mk_error({entrypoint_cannot_be_stateful, Impl, Base, Interface}) ->
+    Msg = io_lib:format("`~s` cannot be stateful because the entrypoint `~s` in the "
+                        "interface `~s` is not stateful",
+                        [name(Impl), name(Base), name(Interface)]),
+    mk_t_err(pos(Impl), Msg);
+mk_error({entrypoint_must_be_payable, Impl, Base, Interface}) ->
+    Msg = io_lib:format("`~s` must be payable because the entrypoint `~s` in the "
+                        "interface `~s` is payable",
+                        [name(Impl), name(Base), name(Interface)]),
+    mk_t_err(pos(Impl), Msg);
+mk_error({unpreserved_payablity, Kind, ContractCon, InterfaceCon}) ->
+    KindStr = case Kind of
+                  contract -> "contract";
+                  contract_interface -> "interface"
+              end,
+    Msg = io_lib:format("Non-payable ~s `~s` cannot implement payable interface `~s`",
+                        [KindStr, name(ContractCon), name(InterfaceCon)]),
+    mk_t_err(pos(ContractCon), Msg);
 mk_error(Err) ->
     Msg = io_lib:format("Unknown error: ~p", [Err]),
     mk_t_err(pos(0, 0), Msg).

src/aeso_ast_to_fcode.erl

@@ -75,7 +75,6 @@
                | {switch, fsplit()}
                | {set_state, state_reg(), fexpr()}
                | {get_state, state_reg()}
-               | {loop, fexpr(), var_name(), fexpr()} | {continue, fexpr()} | {break, fexpr()}
                %% The following (unapplied top-level functions/builtins and
                %% lambdas) are generated by the fcode compiler, but translated
                %% to closures by the lambda lifter.
@@ -150,17 +149,18 @@
 
 -type state_layout() :: {tuple, [state_layout()]} | {reg, state_reg()}.
 
--type env() :: #{ type_env      := type_env(),
-                  fun_env       := fun_env(),
-                  con_env       := con_env(),
-                  child_con_env := child_con_env(),
-                  event_type    => aeso_syntax:typedef(),
-                  builtins      := builtins(),
-                  options       := [option()],
-                  state_layout  => state_layout(),
-                  context       => context(),
-                  vars          => [var_name()],
-                  functions     := #{ fun_name() => fun_def() }
+-type env() :: #{ type_env          := type_env(),
+                  fun_env           := fun_env(),
+                  con_env           := con_env(),
+                  child_con_env     := child_con_env(),
+                  event_type        => aeso_syntax:typedef(),
+                  builtins          := builtins(),
+                  options           := [option()],
+                  state_layout      => state_layout(),
+                  context           => context(),
+                  vars              => [var_name()],
+                  functions         := #{ fun_name() => fun_def() },
+                  saved_fresh_names => #{ var_name() => var_name() }
                }.
 
 -define(HASH_BYTES, 32).
@@ -171,7 +171,7 @@
 %% and produces Fate intermediate code.
 -spec ast_to_fcode(aeso_syntax:ast(), [option()]) -> {env(), fcode()}.
 ast_to_fcode(Code, Options) ->
-    init_fresh_names(),
+    init_fresh_names(Options),
     {Env1, FCode1} = to_fcode(init_env(Options), Code),
     FCode2 = optimize(FCode1, Options),
     Env2 = Env1#{ child_con_env :=
@@ -179,13 +179,18 @@ ast_to_fcode(Code, Options) ->
                         fun (_, FC) -> optimize(FC, Options) end,
                         maps:get(child_con_env, Env1)
                        )},
-    clear_fresh_names(),
-    {Env2, FCode2}.
+    Env3 =
+        case proplists:get_value(debug_info, Options, false) of
+            true  -> Env2#{ saved_fresh_names => get(saved_fresh_names) };
+            false -> Env2
+        end,
+    clear_fresh_names(Options),
+    {Env3, FCode2}.
 
 optimize(FCode1, Options) ->
     Verbose = lists:member(pp_fcode, Options),
     [io:format("-- Before lambda lifting --\n~s\n\n", [format_fcode(FCode1)]) || Verbose],
-    FCode2 = optimize_fcode(FCode1),
+    FCode2 = optimize_fcode(FCode1, Options),
     [ io:format("-- After optimization --\n~s\n\n", [format_fcode(FCode2)]) || Verbose, FCode2 /= FCode1 ],
     FCode3 = lambda_lift(FCode2),
     [ io:format("-- After lambda lifting --\n~s\n\n", [format_fcode(FCode3)]) || Verbose, FCode3 /= FCode2 ],
@@ -243,7 +248,7 @@ builtins() ->
     MkName = fun(NS, Fun) ->
                 list_to_atom(string:to_lower(string:join(NS ++ [Fun], "_")))
              end,
-    Scopes = [{[],           [{"abort", 1}, {"require", 2}]},
+    Scopes = [{[],           [{"abort", 1}, {"require", 2}, {"exit", 1}]},
               {["Chain"],    [{"spend", 2}, {"balance", 1}, {"block_hash", 1}, {"coinbase", none},
                               {"timestamp", none}, {"block_height", none}, {"difficulty", none},
                               {"gas_limit", none}, {"bytecode_hash", 1}, {"create", variable}, {"clone", variable}]},
@@ -327,7 +332,7 @@ get_option(Opt, Env, Default) ->
 %% -- Compilation ------------------------------------------------------------
 
 -spec to_fcode(env(), aeso_syntax:ast()) -> {env(), fcode()}.
-to_fcode(Env, [{Contract, Attrs, Con = {con, _, Name}, _Impls, Decls}|Rest])
+to_fcode(Env, [{Contract, Attrs, {con, _, Name}, _Impls, Decls}|Rest])
   when ?IS_CONTRACT_HEAD(Contract) ->
     case Contract =:= contract_interface of
         false ->
@@ -350,7 +355,7 @@ to_fcode(Env, [{Contract, Attrs, Con = {con, _, Name}, _Impls, Decls}|Rest])
                           event_type    => EventType,
                           payable       => Payable,
                           functions     => add_init_function(
-                                             Env1, Con, StateType,
+                                             Env1,
                                              add_event_function(Env1, EventType, Funs)) },
             case Contract of
                 contract_main -> [] = Rest, {Env1, ConFcode};
@@ -363,8 +368,6 @@ to_fcode(Env, [{Contract, Attrs, Con = {con, _, Name}, _Impls, Decls}|Rest])
             Env1 = decls_to_fcode(Env#{ context => {abstract_contract, Name} }, Decls),
             to_fcode(Env1, Rest)
     end;
-to_fcode(_Env, [NotMain = {NotMainHead, _ ,_ , _}]) when NotMainHead =/= contract_def ->
-    fcode_error({last_declaration_must_be_main_contract, NotMain});
 to_fcode(Env, [{namespace, _, {con, _, Con}, Decls} | Code]) ->
     Env1 = decls_to_fcode(Env#{ context => {namespace, Con} }, Decls),
     to_fcode(Env1, Code).
@@ -378,22 +381,15 @@ decls_to_fcode(Env, Decls) ->
                 end, Env1, Decls).
 
 -spec decl_to_fcode(env(), aeso_syntax:decl()) -> env().
-decl_to_fcode(Env = #{context := {contract_def, _}}, {fun_decl, _, Id, _}) ->
-    case is_no_code(Env) of
-        false -> fcode_error({missing_definition, Id});
-        true  -> Env
-    end;
 decl_to_fcode(Env, {fun_decl, _, _, _})  -> Env;
 decl_to_fcode(Env, {type_def, _Ann, Name, Args, Def}) ->
     typedef_to_fcode(Env, Name, Args, Def);
-decl_to_fcode(Env = #{ functions := Funs }, {letfun, Ann, Id = {id, _, Name}, Args, Ret, [{guarded, _, [], Body}]}) ->
+decl_to_fcode(Env = #{ functions := Funs }, {letfun, Ann, {id, _, Name}, Args, Ret, [{guarded, _, [], Body}]}) ->
     Attrs = get_attributes(Ann),
     FName = lookup_fun(Env, qname(Env, Name)),
     FArgs = args_to_fcode(Env, Args),
     FRet  = type_to_fcode(Env, Ret),
     FBody = expr_to_fcode(Env#{ vars => [X || {X, _} <- FArgs] }, Body),
-    [ ensure_first_order_entrypoint(Ann, Id, Args, Ret, FArgs, FRet)
-      || aeso_syntax:get_ann(entrypoint, Ann, false) ],
     Def   = #{ attrs  => Attrs,
                args   => FArgs,
                return => FRet,
@@ -402,8 +398,7 @@ decl_to_fcode(Env = #{ functions := Funs }, {letfun, Ann, Id = {id, _, Name}, Ar
     Env#{ functions := NewFuns }.
 
 -spec typedef_to_fcode(env(), aeso_syntax:id(), [aeso_syntax:tvar()], aeso_syntax:typedef()) -> env().
-typedef_to_fcode(Env, Id = {id, _, Name}, Xs, Def) ->
-    check_state_and_event_types(Env, Id, Xs),
+typedef_to_fcode(Env, {id, _, Name}, Xs, Def) ->
     Q = qname(Env, Name),
     FDef = fun(Args) when length(Args) == length(Xs) ->
                 Sub = maps:from_list(lists:zip([X || {tvar, _, X} <- Xs], Args)),
@@ -467,14 +462,6 @@ compute_state_layout(R, [H | T]) ->
 compute_state_layout(R, _) ->
     {R + 1, {reg, R}}.
 
-check_state_and_event_types(#{ context := {contract_def, _} }, Id, [_ | _]) ->
-    case Id of
-        {id, _, "state"} -> fcode_error({parameterized_state, Id});
-        {id, _, "event"} -> fcode_error({parameterized_event, Id});
-        _                -> ok
-    end;
-check_state_and_event_types(_, _, _) -> ok.
-
 -spec type_to_fcode(env(), aeso_syntax:type()) -> ftype().
 type_to_fcode(Env, Type) ->
     type_to_fcode(Env, #{}, Type).
@@ -492,8 +479,6 @@ type_to_fcode(Env, Sub, {record_t, Fields}) ->
     type_to_fcode(Env, Sub, {tuple_t, [], lists:map(FieldType, Fields)});
 type_to_fcode(_Env, _Sub, {bytes_t, _, N}) ->
     {bytes, N};
-type_to_fcode(_Env, _Sub, {tvar, Ann, "void"}) ->
-    fcode_error({found_void, Ann});
 type_to_fcode(_Env, Sub, {tvar, _, X}) ->
     maps:get(X, Sub, {tvar, X});
 type_to_fcode(_Env, _Sub, {fun_t, Ann, _, var_args, _}) ->
@@ -555,7 +540,7 @@ expr_to_fcode(_Env, _Type, {bytes,           _, B}) -> {lit, {bytes, B}};
 
 %% Variables
 expr_to_fcode(Env, _Type, {id, _, X})  -> resolve_var(Env, [X]);
-expr_to_fcode(Env, Type, {qid, Ann, X}) ->
+expr_to_fcode(Env, Type, {qid, _, X}) ->
     case resolve_var(Env, X) of
         {builtin_u, B, Ar} when B =:= oracle_query;
                                 B =:= oracle_get_question;
@@ -566,13 +551,11 @@ expr_to_fcode(Env, Type, {qid, Ann, X}) ->
                                 B =:= oracle_check_query ->
             OType = get_oracle_type(B, Type),
             {oracle, QType, RType} = type_to_fcode(Env, OType),
-            validate_oracle_type(Ann, OType, QType, RType),
             TypeArgs = [{lit, {typerep, QType}}, {lit, {typerep, RType}}],
             {builtin_u, B, Ar, TypeArgs};
         {builtin_u, B = aens_resolve, Ar} ->
             {fun_t, _, _, _, ResType} = Type,
             AensType = type_to_fcode(Env, ResType),
-            validate_aens_resolve_type(Ann, ResType, AensType),
             TypeArgs = [{lit, {typerep, AensType}}],
             {builtin_u, B, Ar, TypeArgs};
         {builtin_u, B = bytes_split, Ar} ->
@@ -652,22 +635,11 @@ expr_to_fcode(Env, {record_t, FieldTypes}, {record, _Ann, Rec, Fields}) ->
 expr_to_fcode(Env, _Type, {list, _, Es}) ->
     lists:foldr(fun(E, L) -> {op, '::', [expr_to_fcode(Env, E), L]} end,
                 nil, Es);
+
 expr_to_fcode(Env, _Type, {app, _, {'..', _}, [A, B]}) ->
-    AV = fresh_name(), % var to keep B
-    WithA = fun(X) -> {'let', AV, expr_to_fcode(Env, A), X} end,
-    St = fresh_name(), % loop state
-    ItProj = {proj, {var, St}, 1},
-    AcProj = {proj, {var, St}, 0},
-    Init = {tuple, [nil, expr_to_fcode(Env, B)]},
-    Loop = {loop, Init, St,
-            make_if(
-              {op, '>=', [ItProj, {var, AV}]},
-              {continue, {tuple, [{op, '::', [ItProj, AcProj]},
-                                  {op, '-', [ItProj, {lit, {int, 1}}]}
-                                 ]}},
-              {break, AcProj}
-             )},
-    WithA(Loop);
+    {def_u, FromTo, _} = resolve_fun(Env, ["ListInternal", "from_to"]),
+    {def, FromTo, [expr_to_fcode(Env, A), expr_to_fcode(Env, B)]};
+
 expr_to_fcode(Env, _Type, {list_comp, _, Yield, []}) ->
     {op, '::', [expr_to_fcode(Env, Yield), nil]};
 expr_to_fcode(Env, _Type, {list_comp, As, Yield, [{comprehension_bind, Pat = {typed, _, _, PatType}, BindExpr}|Rest]}) ->
@@ -727,7 +699,7 @@ expr_to_fcode(Env, _Type, {app, _Ann, {Op, _}, [A]}) when is_atom(Op) ->
     end;
 
 %% Function calls
-expr_to_fcode(Env, Type, {app, _, Fun = {typed, _, FunE, {fun_t, _, NamedArgsT, ArgsT, _}}, Args}) ->
+expr_to_fcode(Env, _, {app, _, Fun = {typed, _, FunE, {fun_t, _, NamedArgsT, ArgsT, Type}}, Args}) ->
     Args1 = get_named_args(NamedArgsT, Args),
     FArgs = [expr_to_fcode(Env, Arg) || Arg <- Args1],
     case expr_to_fcode(Env, Fun) of
@@ -836,53 +808,6 @@ get_oracle_type(oracle_check,        {fun_t, _, _, [OType | _], _}) -> OType;
 get_oracle_type(oracle_check_query,  {fun_t, _, _, [OType | _], _}) -> OType;
 get_oracle_type(oracle_respond,      {fun_t, _, _, [OType | _], _}) -> OType.
 
-validate_oracle_type(Ann, Type, QType, RType) ->
-    ensure_monomorphic(QType, {invalid_oracle_type, polymorphic,  query,    Ann, Type}),
-    ensure_monomorphic(RType, {invalid_oracle_type, polymorphic,  response, Ann, Type}),
-    ensure_first_order(QType, {invalid_oracle_type, higher_order, query,    Ann, Type}),
-    ensure_first_order(RType, {invalid_oracle_type, higher_order, response, Ann, Type}),
-    ok.
-
-validate_aens_resolve_type(Ann, {app_t, _, _, [Type]}, {variant, [[], [FType]]}) ->
-    case FType of
-        string         -> ok;
-        address        -> ok;
-        contract       -> ok;
-        {oracle, _, _} -> ok;
-        oracle_query   -> ok;
-        _              -> fcode_error({invalid_aens_resolve_type, Ann, Type})
-    end.
-
-ensure_first_order_entrypoint(Ann, Id = {id, _, Name}, Args, Ret, FArgs, FRet) ->
-    [ ensure_first_order(FT, {invalid_entrypoint, higher_order, Ann1, Id, {argument, X, T}})
-      || {{typed, Ann1, X, T}, {_, FT}} <- lists:zip(Args, FArgs) ],
-    [ ensure_first_order(FRet, {invalid_entrypoint, higher_order, Ann, Id, {result, Ret}})
-      || Name /= "init" ],  %% init can return higher-order values, since they're written to the store
-                            %% rather than being returned.
-    ok.
-
-ensure_monomorphic(Type, Err) ->
-    case is_monomorphic(Type) of
-        true  -> ok;
-        false -> fcode_error(Err)
-    end.
-
-ensure_first_order(Type, Err) ->
-    case is_first_order(Type) of
-        true  -> ok;
-        false -> fcode_error(Err)
-    end.
-
-is_monomorphic({tvar, _})              -> false;
-is_monomorphic(Ts) when is_list(Ts)    -> lists:all(fun is_monomorphic/1, Ts);
-is_monomorphic(Tup) when is_tuple(Tup) -> is_monomorphic(tuple_to_list(Tup));
-is_monomorphic(_)                      -> true.
-
-is_first_order({function, _, _})       -> false;
-is_first_order(Ts) when is_list(Ts)    -> lists:all(fun is_first_order/1, Ts);
-is_first_order(Tup) when is_tuple(Tup) -> is_first_order(tuple_to_list(Tup));
-is_first_order(_)                      -> true.
-
 %% -- Pattern matching --
 
 -spec alts_to_fcode(env(), ftype(), var_name(), [aeso_syntax:alt()], aeso_syntax:expr()) -> fsplit().
@@ -1215,11 +1140,11 @@ builtin_to_fcode(_Layout, Builtin, Args) ->
 
 %% -- Init function --
 
-add_init_function(Env, Main, StateType, Funs0) ->
+add_init_function(Env, Funs0) ->
     case is_no_code(Env) of
         true  -> Funs0;
         false ->
-            Funs     = add_default_init_function(Env, Main, StateType, Funs0),
+            Funs     = add_default_init_function(Env, Funs0),
             InitName = {entrypoint, <<"init">>},
             InitFun  = #{ body := InitBody} = maps:get(InitName, Funs),
             Funs1 = Funs#{ InitName => InitFun#{ return => {tuple, []},
@@ -1227,16 +1152,14 @@ add_init_function(Env, Main, StateType, Funs0) ->
             Funs1
     end.
 
-add_default_init_function(_Env, Main, StateType, Funs) ->
+add_default_init_function(_Env, Funs) ->
     InitName = {entrypoint, <<"init">>},
     case maps:get(InitName, Funs, none) of
-        %% Only add default init function if state is unit.
-        none when StateType == {tuple, []} ->
+        none ->
             Funs#{ InitName => #{attrs  => [],
                                  args   => [],
                                  return => {tuple, []},
                                  body   => {tuple, []}} };
-        none -> fcode_error({missing_init_function, Main});
         _    -> Funs
     end.
 
@@ -1350,9 +1273,6 @@ lambda_lift_expr(Layout, Expr) ->
         {proj, A, I}           -> {proj, lambda_lift_expr(Layout, A), I};
         {set_proj, A, I, B}    -> {set_proj, lambda_lift_expr(Layout, A), I, lambda_lift_expr(Layout, B)};
         {op, Op, As}           -> {op, Op, lambda_lift_exprs(Layout, As)};
-        {loop, Init, I, Body}  -> {loop, lambda_lift_expr(Layout, Init), I, lambda_lift_expr(Layout, Body)};
-        {break, E}             -> {break, lambda_lift_expr(Layout, E)};
-        {continue, E}          -> {continue, lambda_lift_expr(Layout, E)};
         {'let', X, A, B}       -> {'let', X, lambda_lift_expr(Layout, A), lambda_lift_expr(Layout, B)};
         {funcall, A, Bs}       -> {funcall, lambda_lift_expr(Layout, A), lambda_lift_exprs(Layout, Bs)};
         {set_state, R, A}      -> {set_state, R, lambda_lift_expr(Layout, A)};
@@ -1373,20 +1293,28 @@ lambda_lift_exprs(Layout, As) -> [lambda_lift_expr(Layout, A) || A <- As].
 %% - Constant propagation
 %% - Inlining
 
--spec optimize_fcode(fcode()) -> fcode().
-optimize_fcode(Code = #{ functions := Funs }) ->
-    Code1 = Code#{ functions := maps:map(fun(Name, Def) -> optimize_fun(Code, Name, Def) end, Funs) },
+-spec optimize_fcode(fcode(), [option()]) -> fcode().
+optimize_fcode(Code = #{ functions := Funs }, Options) ->
+    Code1 = Code#{ functions := maps:map(fun(Name, Def) -> optimize_fun(Code, Name, Def, Options) end, Funs) },
     eliminate_dead_code(Code1).
 
--spec optimize_fun(fcode(), fun_name(), fun_def()) -> fun_def().
-optimize_fun(Fcode, Fun, Def = #{ body := Body }) ->
-    %% io:format("Optimizing ~p =\n~s\n", [_Fun, prettypr:format(pp_fexpr(_Body))]),
-    Def#{ body := drop_unused_lets(
-                  simplifier(
-                  let_floating(
-                  bind_subexpressions(
-                  inline_local_functions(
-                  inliner(Fcode, Fun, Body)))))) }.
+-spec optimize_fun(fcode(), fun_name(), fun_def(), [option()]) -> fun_def().
+optimize_fun(Fcode, Fun, Def = #{ body := Body0 }, Options) ->
+    Inliner              = proplists:get_value(optimize_inliner,                Options, true),
+    InlineLocalFunctions = proplists:get_value(optimize_inline_local_functions, Options, true),
+    BindSubexpressions   = proplists:get_value(optimize_bind_subexpressions,    Options, true),
+    LetFloating          = proplists:get_value(optimize_let_floating,           Options, true),
+    Simplifier           = proplists:get_value(optimize_simplifier,             Options, true),
+    DropUnusedLets       = proplists:get_value(optimize_drop_unused_lets,       Options, true),
+
+    Body1 = if Inliner              -> inliner   (Fcode, Fun, Body0); true -> Body0 end,
+    Body2 = if InlineLocalFunctions -> inline_local_functions(Body1); true -> Body1 end,
+    Body3 = if BindSubexpressions   -> bind_subexpressions   (Body2); true -> Body2 end,
+    Body4 = if LetFloating          -> let_floating          (Body3); true -> Body3 end,
+    Body5 = if Simplifier           -> simplifier            (Body4); true -> Body4 end,
+    Body6 = if DropUnusedLets       -> drop_unused_lets      (Body5); true -> Body5 end,
+
+    Def#{ body := Body6 }.
 
 %% --- Inlining ---
 
@@ -1668,9 +1596,6 @@ read_only({switch, Split})         -> read_only(Split);
 read_only({split, _, _, Cases})    -> read_only(Cases);
 read_only({nosplit, E})            -> read_only(E);
 read_only({'case', _, Split})      -> read_only(Split);
-read_only({loop, Init, _, Body})   -> read_only(Init) andalso read_only(Body);
-read_only({break, E})              -> read_only(E);
-read_only({continue, E})           -> read_only(E);
 read_only({'let', _, A, B})        -> read_only([A, B]);
 read_only({funcall, _, _})         -> false;
 read_only({closure, _, _})         -> internal_error(no_closures_here);
@@ -1809,12 +1734,29 @@ resolve_fun(#{ fun_env := Funs, builtins := Builtin } = Env, Q) ->
         {{Fun, Ar}, _}         -> {def_u, Fun, Ar}
     end.
 
-init_fresh_names() ->
+init_fresh_names(Options) ->
+    proplists:get_value(debug_info, Options, false) andalso init_saved_fresh_names(),
     put('%fresh', 0).
 
-clear_fresh_names() ->
+clear_fresh_names(Options) ->
+    proplists:get_value(debug_info, Options, false) andalso clear_saved_fresh_names(),
     erase('%fresh').
 
+init_saved_fresh_names() ->
+    put(saved_fresh_names, #{}).
+
+clear_saved_fresh_names() ->
+    erase(saved_fresh_names).
+
+-spec fresh_name_save(string()) -> var_name().
+fresh_name_save(Name) ->
+    Fresh = fresh_name(),
+    case get(saved_fresh_names) of
+        undefined -> ok;
+        Old       -> put(saved_fresh_names, Old#{Fresh => Name})
+    end,
+    Fresh.
+
 -spec fresh_name() -> var_name().
 fresh_name() -> fresh_name("%").
 
@@ -1868,9 +1810,6 @@ free_vars(Expr) ->
         {proj, A, _}         -> free_vars(A);
         {set_proj, A, _, B}  -> free_vars([A, B]);
         {op, _, As}          -> free_vars(As);
-        {loop, Init, Var, Body} -> free_vars(Init) ++ (free_vars(Body) -- [Var]);
-        {break, E}           -> free_vars(E);
-        {continue, E}        -> free_vars(E);
         {'let', X, A, B}     -> free_vars([A, {lam, [X], B}]);
         {funcall, A, Bs}     -> free_vars([A | Bs]);
         {set_state, _, A}    -> free_vars(A);
@@ -1902,9 +1841,6 @@ used_defs(Expr) ->
         {proj, A, _}         -> used_defs(A);
         {set_proj, A, _, B}  -> used_defs([A, B]);
         {op, _, As}          -> used_defs(As);
-        {loop, I, _, B}      -> used_defs(I) ++ used_defs(B);
-        {break, E}           -> used_defs(E);
-        {continue, E}        -> used_defs(E);
         {'let', _, A, B}     -> used_defs([A, B]);
         {funcall, A, Bs}     -> used_defs([A | Bs]);
         {set_state, _, A}    -> used_defs(A);
@@ -1941,9 +1877,6 @@ bottom_up(F, Env, Expr) ->
         {get_state, _}                   -> Expr;
         {closure, F, CEnv}               -> {closure, F, bottom_up(F, Env, CEnv)};
         {switch, Split}                  -> {switch, bottom_up(F, Env, Split)};
-        {loop, Init, Var, Body}          -> {loop, bottom_up(F, Env, Init), Var, bottom_up(F, Env, Body)};
-        {break, E}                       -> {break, bottom_up(F, Env, E)};
-        {continue, E}                    -> {continue, bottom_up(F, Env, E)};
         {lam, Xs, B}                     -> {lam, Xs, bottom_up(F, Env, B)};
         {'let', X, E, Body}              ->
             E1 = bottom_up(F, Env, E),
@@ -1952,7 +1885,7 @@ bottom_up(F, Env, Expr) ->
                                (_)            -> true end,
             case ShouldFreshen(X) of
                 true ->
-                    Z = fresh_name(),
+                    Z = fresh_name_save(X),
                     Env1 = Env#{ Z => E1 },
                     {'let', Z, E1, bottom_up(F, Env1, rename([{X, Z}], Body))};
                 false ->
@@ -2005,11 +1938,6 @@ rename(Ren, Expr) ->
         {lam, Xs, B} ->
             {Zs, Ren1} = rename_bindings(Ren, Xs),
             {lam, Zs, rename(Ren1, B)};
-        {loop, Init, Var, Body} ->
-            {Z, Ren1} = rename_binding(Ren, Var),
-            {loop, rename(Ren, Init), Z, rename(Ren1, Body)};
-        {break, E}           -> {break, rename(Ren, E)};
-        {continue, E}        -> {continue, rename(Ren, E)};
         {'let', X, E, Body} ->
             {Z, Ren1} = rename_binding(Ren, X),
             {'let', Z, rename(Ren, E), rename(Ren1, Body)}
@@ -2122,7 +2050,9 @@ setnth(I, X, Xs) ->
 -dialyzer({nowarn_function, [fcode_error/1, internal_error/1]}).
 
 fcode_error(Error) ->
-    aeso_errors:throw(aeso_code_errors:format(Error)).
+    Pos = aeso_errors:pos(0, 0),
+    Msg = lists:flatten(io_lib:format("Unknown error: ~p\n", [Error])),
+    aeso_errors:throw(aeso_errors:new(code_error, Pos, Msg)).
 
 internal_error(Error) ->
     Msg = lists:flatten(io_lib:format("~p\n", [Error])),
@@ -2201,13 +2131,6 @@ pp_fexpr({tuple, Es}) ->
     pp_parens(pp_par(pp_punctuate(pp_text(","), [pp_fexpr(E) || E <- Es])));
 pp_fexpr({proj, E, I}) ->
     pp_beside([pp_fexpr(E), pp_text("."), pp_int(I)]);
-pp_fexpr({loop, Init, Var, Body}) ->
-    pp_par(
-      [ pp_beside([pp_text("loop"), pp_fexpr(Init), pp_text("as"), pp_text(Var)])
-      , pp_fexpr(Body)
-      ]);
-pp_fexpr({break, E}) -> pp_beside([pp_text("break"), pp_fexpr(E)]);
-pp_fexpr({continue, E}) -> pp_beside([pp_text("continue"), pp_fexpr(E)]);
 pp_fexpr({lam, Xs, A}) ->
     pp_par([pp_fexpr({tuple, [{var, X} || X <- Xs]}), pp_text("=>"),
             prettypr:nest(2, pp_fexpr(A))]);

src/aeso_code_errors.erl

@@ -1,94 +0,0 @@
-%%%-------------------------------------------------------------------
-%%% @author Ulf Norell
-%%% @copyright (C) 2019, Aeternity Anstalt
-%%% @doc
-%%%     Formatting of code generation errors.
-%%% @end
-%%%
-%%%-------------------------------------------------------------------
--module(aeso_code_errors).
-
--export([format/1, pos/1]).
-
-format({last_declaration_must_be_main_contract, Decl = {Kind, _, {con, _, C}, _}}) ->
-    Msg = io_lib:format("Expected a main contract as the last declaration instead of the ~p '~s'",
-                        [Kind, C]),
-    mk_err(pos(Decl), Msg);
-format({missing_init_function, Con}) ->
-    Msg = io_lib:format("Missing init function for the contract '~s'.", [pp_expr(Con)]),
-    Cxt = "The 'init' function can only be omitted if the state type is 'unit'.",
-    mk_err(pos(Con), Msg, Cxt);
-format({missing_definition, Id}) ->
-    Msg = io_lib:format("Missing definition of function '~s'.", [pp_expr(Id)]),
-    mk_err(pos(Id), Msg);
-format({parameterized_state, Decl}) ->
-    Msg = "The state type cannot be parameterized.",
-    mk_err(pos(Decl), Msg);
-format({parameterized_event, Decl}) ->
-    Msg = "The event type cannot be parameterized.",
-    mk_err(pos(Decl), Msg);
-format({invalid_entrypoint, Why, Ann, {id, _, Name}, Thing}) ->
-    What = case Why of higher_order -> "higher-order (contains function types)";
-                       polymorphic  -> "polymorphic (contains type variables)" end,
-    ThingS = case Thing of
-                 {argument, X, T} -> io_lib:format("argument\n~s\n", [pp_typed(X, T)]);
-                 {result, T}      -> io_lib:format("return type\n~s\n", [pp_type(2, T)])
-             end,
-    Bad = case Thing of
-              {argument, _, _} -> io_lib:format("has a ~s type", [What]);
-              {result, _}      -> io_lib:format("is ~s", [What])
-          end,
-    Msg = io_lib:format("The ~sof entrypoint '~s' ~s.",
-                        [ThingS, Name, Bad]),
-    case Why of
-        higher_order -> mk_err(pos(Ann), Msg)
-    end;
-format({invalid_aens_resolve_type, Ann, T}) ->
-    Msg = io_lib:format("Invalid return type of AENS.resolve:\n"
-                        "~s\n"
-                        "It must be a string or a pubkey type (address, oracle, etc).",
-                        [pp_type(2, T)]),
-    mk_err(pos(Ann), Msg);
-format({invalid_oracle_type, Why, What, Ann, Type}) ->
-    WhyS = case Why of higher_order -> "higher-order (contain function types)";
-                       polymorphic  -> "polymorphic (contain type variables)" end,
-    Msg = io_lib:format("Invalid oracle type\n~s", [pp_type(2, Type)]),
-    Cxt = io_lib:format("The ~s type must not be ~s.", [What, WhyS]),
-    mk_err(pos(Ann), Msg, Cxt);
-format({var_args_not_set, Expr}) ->
-    mk_err( pos(Expr), "Could not deduce type of variable arguments list"
-          , "When compiling " ++ pp_expr(Expr)
-          );
-format({found_void, Ann}) ->
-    mk_err(pos(Ann), "Found a void-typed value.", "`void` is a restricted, uninhabited type. Did you mean `unit`?");
-
-format(Err) ->
-    mk_err(aeso_errors:pos(0, 0), io_lib:format("Unknown error: ~p\n", [Err])).
-
-pos(Ann) ->
-    File = aeso_syntax:get_ann(file, Ann, no_file),
-    Line = aeso_syntax:get_ann(line, Ann, 0),
-    Col  = aeso_syntax:get_ann(col, Ann, 0),
-    aeso_errors:pos(File, Line, Col).
-
-pp_typed(E, T) ->
-    prettypr:format(prettypr:nest(2,
-    lists:foldr(fun prettypr:beside/2, prettypr:empty(),
-                [aeso_pretty:expr(E), prettypr:text(" : "),
-                 aeso_pretty:type(T)]))).
-
-pp_expr(E) ->
-    pp_expr(0, E).
-
-pp_expr(N, E) ->
-    prettypr:format(prettypr:nest(N, aeso_pretty:expr(E))).
-
-pp_type(N, T) ->
-    prettypr:format(prettypr:nest(N, aeso_pretty:type(T))).
-
-mk_err(Pos, Msg) ->
-    aeso_errors:new(code_error, Pos, lists:flatten(Msg)).
-
-mk_err(Pos, Msg, Cxt) ->
-    aeso_errors:new(code_error, Pos, lists:flatten(Msg), lists:flatten(Cxt)).
-

src/aeso_compiler.erl

@@ -112,10 +112,12 @@ from_string(ContractString, Options) ->
 
 from_string1(ContractString, Options) ->
     #{ fcode := FCode
-     , fcode_env := #{child_con_env := ChildContracts}
+     , fcode_env := FCodeEnv
      , folded_typed_ast := FoldedTypedAst
      , warnings := Warnings } = string_to_code(ContractString, Options),
-    FateCode = aeso_fcode_to_fate:compile(ChildContracts, FCode, Options),
+    #{ child_con_env := ChildContracts } = FCodeEnv,
+    SavedFreshNames = maps:get(saved_fresh_names, FCodeEnv, #{}),
+    {FateCode, VarsRegs} = aeso_fcode_to_fate:compile(ChildContracts, FCode, SavedFreshNames, Options),
     pp_assembler(FateCode, Options),
     ByteCode = aeb_fate_code:serialize(FateCode, []),
     {ok, Version} = version(),
@@ -128,7 +130,13 @@ from_string1(ContractString, Options) ->
             payable => maps:get(payable, FCode),
             warnings => Warnings
            },
-    {ok, maybe_generate_aci(Res, FoldedTypedAst, Options)}.
+    ResDbg = Res#{variables_registers => VarsRegs},
+    FinalRes =
+        case proplists:get_value(debug_info, Options, false) of
+            true  -> ResDbg;
+            false -> Res
+        end,
+    {ok, maybe_generate_aci(FinalRes, FoldedTypedAst, Options)}.
 
 maybe_generate_aci(Result, FoldedTypedAst, Options) ->
     case proplists:get_value(aci, Options) of
@@ -185,7 +193,7 @@ check_call1(ContractString0, FunName, Args, Options) ->
         #{fcode := OrgFcode
         , fcode_env := #{child_con_env := ChildContracts}
         , ast := Ast} = string_to_code(ContractString0, Options),
-        FateCode = aeso_fcode_to_fate:compile(ChildContracts, OrgFcode, []),
+        {FateCode, _} = aeso_fcode_to_fate:compile(ChildContracts, OrgFcode, #{}, []),
         %% collect all hashes and compute the first name without hash collision to
         SymbolHashes = maps:keys(aeb_fate_code:symbols(FateCode)),
         CallName = first_none_match(?CALL_NAME, SymbolHashes,
@@ -349,7 +357,7 @@ get_decode_type(FunName, [{Contract, Ann, _, _, Defs}]) when ?IS_CONTRACT_HEAD(C
                 "init" -> {ok, [], {tuple_t, [], []}};
                  _ ->
                     Msg = io_lib:format("Function '~s' is missing in contract", [FunName]),
-                    Pos = aeso_code_errors:pos(Ann),
+                    Pos = aeso_errors:pos(Ann),
                     aeso_errors:throw(aeso_errors:new(data_error, Pos, Msg))
             end
     end;

src/aeso_errors.erl

@@ -34,6 +34,7 @@
         , new/2
         , new/3
         , new/4
+        , pos/1
         , pos/2
         , pos/3
         , pp/1
@@ -53,6 +54,12 @@ new(Type, Pos, Msg) ->
 new(Type, Pos, Msg, Ctxt) ->
     #err{ type = Type, pos = Pos, message = Msg, context = Ctxt }.
 
+pos(Ann) ->
+    File = aeso_syntax:get_ann(file, Ann, no_file),
+    Line = aeso_syntax:get_ann(line, Ann, 0),
+    Col  = aeso_syntax:get_ann(col, Ann, 0),
+    pos(File, Line, Col).
+
 pos(Line, Col) ->
     #pos{ line = Line, col = Col }.
 

src/aeso_fcode_to_fate.erl

@@ -9,7 +9,7 @@
 %%%-------------------------------------------------------------------
 -module(aeso_fcode_to_fate).
 
--export([compile/2, compile/3, term_to_fate/1, term_to_fate/2]).
+-export([compile/3, compile/4, term_to_fate/1, term_to_fate/2]).
 
 -ifdef(TEST).
 -export([optimize_fun/4, to_basic_blocks/1]).
@@ -19,7 +19,6 @@
 
 -type scode()  :: [sinstr()].
 -type sinstr() :: {switch, arg(), stype(), [maybe_scode()], maybe_scode()}  %% last arg is catch-all
-                | {loop, scode(), var(), scode(), reference(), reference()}
                 | switch_body
                 | loop
                 | tuple() | atom().    %% FATE instruction
@@ -46,7 +45,14 @@
 -define(s(N), {store, N}).
 -define(void, {var, 9999}).
 
--record(env, { contract, vars = [], locals = [], break_ref = none, cont_ref = none, loop_it = none, current_function, tailpos = true, child_contracts = #{}, options = []}).
+-record(env, { contract,
+               vars              = [],
+               locals            = [],
+               current_function,
+               tailpos           = true,
+               child_contracts   = #{},
+               saved_fresh_names = #{},
+               options           = [] }).
 
 %% -- Debugging --------------------------------------------------------------
 
@@ -65,21 +71,34 @@ debug(Tag, Options, Fun) ->
 
 -dialyzer({nowarn_function, [code_error/1]}).
 code_error(Err) ->
-    aeso_errors:throw(aeso_code_errors:format(Err)).
+    Pos = aeso_errors:pos(0, 0),
+    Msg = lists:flatten(io_lib:format("Unknown error: ~p\n", [Err])),
+    aeso_errors:throw(aeso_errors:new(code_error, Pos, Msg)).
 
 %% -- Main -------------------------------------------------------------------
 
 %% @doc Main entry point.
-compile(FCode, Options) ->
-    compile(#{}, FCode, Options).
-compile(ChildContracts, FCode, Options) ->
+compile(FCode, SavedFreshNames, Options) ->
+    compile(#{}, FCode, SavedFreshNames, Options).
+compile(ChildContracts, FCode, SavedFreshNames, Options) ->
+    try
+        compile1(ChildContracts, FCode, SavedFreshNames, Options)
+    after
+        put(variables_registers, undefined)
+    end.
+
+compile1(ChildContracts, FCode, SavedFreshNames, Options) ->
     #{ contract_name := ContractName,
        functions     := Functions } = FCode,
-    SFuns  = functions_to_scode(ChildContracts, ContractName, Functions, Options),
+    SFuns  = functions_to_scode(ChildContracts, ContractName, Functions, SavedFreshNames, Options),
     SFuns1 = optimize_scode(SFuns, Options),
     FateCode = to_basic_blocks(SFuns1),
     ?debug(compile, Options, "~s\n", [aeb_fate_asm:pp(FateCode)]),
-    FateCode.
+    FateCode1 = case proplists:get_value(include_child_contract_symbols, Options, false) of
+                    false -> FateCode;
+                    true -> add_child_symbols(ChildContracts, FateCode)
+                end,
+    {FateCode1, get_variables_registers()}.
 
 make_function_id(X) ->
     aeb_fate_code:symbol_identifier(make_function_name(X)).
@@ -88,22 +107,48 @@ make_function_name(event)              -> <<"Chain.event">>;
 make_function_name({entrypoint, Name}) -> Name;
 make_function_name({local_fun, Xs})    -> list_to_binary("." ++ string:join(Xs, ".")).
 
-functions_to_scode(ChildContracts, ContractName, Functions, Options) ->
+add_child_symbols(ChildContracts, FateCode) ->
+    Funs = lists:flatten([ maps:keys(ChildFuns) || {_, #{functions := ChildFuns}} <- maps:to_list(ChildContracts) ]),
+    Symbols = maps:from_list([ {make_function_id(FName), make_function_name(FName)} || FName <- Funs ]),
+    aeb_fate_code:update_symbols(FateCode, Symbols).
+
+functions_to_scode(ChildContracts, ContractName, Functions, SavedFreshNames, Options) ->
     FunNames = maps:keys(Functions),
     maps:from_list(
-        [ {make_function_name(Name), function_to_scode(ChildContracts, ContractName, FunNames, Name, Attrs, Args, Body, Type, Options)}
+        [ {make_function_name(Name), function_to_scode(ChildContracts, ContractName, FunNames, Name, Attrs, Args, Body, Type, SavedFreshNames, Options)}
         || {Name, #{args   := Args,
                     body   := Body,
                     attrs  := Attrs,
                     return := Type}} <- maps:to_list(Functions)]).
 
-function_to_scode(ChildContracts, ContractName, Functions, Name, Attrs0, Args, Body, ResType, Options) ->
+function_to_scode(ChildContracts, ContractName, Functions, Name, Attrs0, Args, Body, ResType, SavedFreshNames, Options) ->
     {ArgTypes, ResType1} = typesig_to_scode(Args, ResType),
     Attrs = Attrs0 -- [stateful], %% Only track private and payable from here.
-    Env = init_env(ChildContracts, ContractName, Functions, Name, Args, Options),
+    Env = init_env(ChildContracts, ContractName, Functions, Name, Args, SavedFreshNames, Options),
+    [ add_variables_register(Env, Arg, Register) ||
+        proplists:get_value(debug_info, Options, false),
+        {Arg, Register} <- Env#env.vars ],
     SCode = to_scode(Env, Body),
     {Attrs, {ArgTypes, ResType1}, SCode}.
 
+get_variables_registers() ->
+    case get(variables_registers) of
+        undefined -> #{};
+        Vs        -> Vs
+    end.
+
+add_variables_register(Env = #env{saved_fresh_names = SavedFreshNames}, Name, Register) ->
+    Olds = get_variables_registers(),
+    RealName = maps:get(Name, SavedFreshNames, Name),
+    FunName =
+        case Env#env.current_function of
+            event -> "Chain.event";
+            {entrypoint, BinName} -> binary_to_list(BinName);
+            {local_fun, QualName} -> lists:last(QualName)
+        end,
+    New = {Env#env.contract, FunName, RealName},
+    put(variables_registers, Olds#{New => Register}).
+
 -define(tvars, '$tvars').
 
 typesig_to_scode(Args, Res) ->
@@ -148,22 +193,21 @@ types_to_scode(Ts) -> lists:map(fun type_to_scode/1, Ts).
 
 %% -- Environment functions --
 
-init_env(ChildContracts, ContractName, FunNames, Name, Args, Options) ->
+init_env(ChildContracts, ContractName, FunNames, Name, Args, SavedFreshNames, Options) ->
     #env{ vars      = [ {X, {arg, I}} || {I, {X, _}} <- with_ixs(Args) ],
           contract  = ContractName,
           child_contracts = ChildContracts,
           locals    = FunNames,
           current_function = Name,
           options = Options,
-          tailpos   = true }.
+          tailpos   = true,
+          saved_fresh_names = SavedFreshNames }.
 
 next_var(#env{ vars = Vars }) ->
     1 + lists:max([-1 | [J || {_, {var, J}} <- Vars]]).
 
-bind_loop(ContRef, BreakRef, It, Env) ->
-    Env#env{break_ref = BreakRef, cont_ref = ContRef, loop_it = It}.
-
 bind_var(Name, Var, Env = #env{ vars = Vars }) ->
+    proplists:get_value(debug_info, Env#env.options, false) andalso add_variables_register(Env, Name, Var),
     Env#env{ vars = [{Name, Var} | Vars] }.
 
 bind_local(Name, Env) ->
@@ -187,9 +231,10 @@ serialize_contract_code(Env, C) ->
             end,
     case maps:get(C, Cache, none) of
         none ->
-            Options  = Env#env.options,
-            FCode    = maps:get(C, Env#env.child_contracts),
-            FateCode = compile(Env#env.child_contracts, FCode, Options),
+            Options = Env#env.options,
+            SavedFreshNames = Env#env.saved_fresh_names,
+            FCode = maps:get(C, Env#env.child_contracts),
+            {FateCode, _} = compile1(Env#env.child_contracts, FCode, SavedFreshNames, Options),
             ByteCode = aeb_fate_code:serialize(FateCode, []),
             {ok, Version} = aeso_compiler:version(),
             OriginalSourceCode = proplists:get_value(original_src, Options, ""),
@@ -372,21 +417,7 @@ to_scode1(Env, {set_state, Reg, Val}) ->
 
 to_scode1(Env, {closure, Fun, FVs}) ->
     to_scode(Env, {tuple, [{lit, {string, make_function_id(Fun)}}, FVs]});
-to_scode1(Env, {loop, Init, It, Expr}) ->
-    ContRef = make_ref(),
-    BreakRef = make_ref(),
-    {ItV, Env1} = bind_local(It, Env),
-    InitS = [to_scode(notail(Env), Init),
-             {jump, ContRef}],
-    ExprS = [aeb_fate_ops:store({var, ItV}, {stack, 0}),
-             to_scode(bind_loop(ContRef, BreakRef, ItV, Env1), Expr),
-             {jump, BreakRef}],
-    [{loop, InitS, It, ExprS, ContRef, BreakRef}];
-to_scode1(Env = #env{cont_ref = ContRef}, {continue, Expr}) ->
-    [to_scode1(notail(Env), Expr),
-     {jump, ContRef}];
-to_scode1(Env, {break, Expr}) ->
-    to_scode1(Env, Expr);
+
 to_scode1(Env, {switch, Case}) ->
     split_to_scode(Env, Case).
 
@@ -525,6 +556,8 @@ builtin_to_scode(Env, bytes_split, [_, _] = Args) ->
     call_to_scode(Env, aeb_fate_ops:bytes_split(?a, ?a, ?a), Args);
 builtin_to_scode(Env, abort, [_] = Args) ->
     call_to_scode(Env, aeb_fate_ops:abort(?a), Args);
+builtin_to_scode(Env, exit, [_] = Args) ->
+    call_to_scode(Env, aeb_fate_ops:exit(?a), Args);
 builtin_to_scode(Env, chain_spend, [_, _] = Args) ->
     call_to_scode(Env, [aeb_fate_ops:spend(?a, ?a),
                         tuple(0)], Args);
@@ -723,15 +756,13 @@ tuple(N) -> aeb_fate_ops:tuple(?a, N).
 
 optimize_scode(Funs, Options) ->
     maps:map(fun(Name, Def) -> optimize_fun(Funs, Name, Def, Options) end,
-             Funs).
+            Funs).
 
 flatten(missing) -> missing;
 flatten(Code)    -> lists:map(fun flatten_s/1, lists:flatten(Code)).
 
 flatten_s({switch, Arg, Type, Alts, Catch}) ->
     {switch, Arg, Type, [flatten(Alt) || Alt <- Alts], flatten(Catch)};
-flatten_s({loop, Init, It, Body, BRef, CRef}) ->
-    {loop, flatten(Init), It, flatten(Body), BRef, CRef};
 flatten_s(I) -> I.
 
 -define(MAX_SIMPL_ITERATIONS, 10).
@@ -828,11 +859,6 @@ ann_live1(LiveTop, {switch, Arg, Type, Alts, Def}, LiveOut) ->
     {Def1,  LiveDef}  = ann_live(LiveTop, Def, LiveOut),
     LiveIn = ordsets:union([Read, LiveDef | LiveAlts]),
     {{switch, Arg, Type, Alts1, Def1}, LiveIn};
-ann_live1(LiveTop, {loop, Init, It, Body, BRef, CRef}, LiveOut) ->
-    {Init1, LiveInit} = ann_live(LiveTop, Init, LiveOut),
-    {Body1, LiveBody} = ann_live(LiveTop, Body, LiveOut),
-    LiveIn = ordsets:union([It, LiveInit, LiveBody]), % TODO not sure about this
-    {{loop, Init1, It, Body1, BRef, CRef}, LiveIn};
 ann_live1(_LiveTop, I, LiveOut) ->
     #{ read := Reads0, write := W } = attributes(I),
     Reads   = lists:filter(fun is_reg/1, Reads0),
@@ -859,7 +885,6 @@ attributes(I) ->
     case I of
         loop                                  -> Impure(pc, []);
         switch_body                           -> Pure(none, []);
-        {jump, _}                             -> Impure(pc, []);
         'RETURN'                              -> Impure(pc, []);
         {'RETURNR', A}                        -> Impure(pc, A);
         {'CALL', A}                           -> Impure(?a, [A]);
@@ -1049,7 +1074,6 @@ var_writes(I) ->
 -spec independent(sinstr_a(), sinstr_a()) -> boolean().
 %% independent({switch, _, _, _, _}, _) -> false;       %% Commented due to Dialyzer whinging
 independent(_, {switch, _, _, _, _}) -> false;
-independent(_, {loop, _, _, _, _, _}) -> false;
 independent({i, _, I}, {i, _, J}) ->
     #{ write := WI, read := RI, pure := PureI } = attributes(I),
     #{ write := WJ, read := RJ, pure := PureJ } = attributes(J),
@@ -1088,8 +1112,6 @@ live_in(R, {i, Ann, _}) -> live_in(R, Ann);
 live_in(R, [I = {i, _, _} | _]) -> live_in(R, I);
 live_in(R, [{switch, A, _, Alts, Def} | _]) ->
     R == A orelse lists:any(fun(Code) -> live_in(R, Code) end, [Def | Alts]);
-live_in(R, [{loop, Init, Var, Expr, _, _}]) ->
-    live_in(Var, Init) orelse (R /= Var andalso live_in(R, Expr));
 live_in(_, missing) -> false;
 live_in(_, []) -> false.
 
@@ -1105,8 +1127,6 @@ simplify([I | Code], Options) ->
 
 simpl_s({switch, Arg, Type, Alts, Def}, Options) ->
     {switch, Arg, Type, [simplify(A, Options) || A <- Alts], simplify(Def, Options)};
-simpl_s({loop, Init, Var, Expr, ContRef, BreakRef}, Options) ->
-    {loop, simplify(Init, Options), Var, simplify(Expr, Options), ContRef, BreakRef};
 simpl_s(I, _) -> I.
 
 %% Safe-guard against loops in the rewriting. Shouldn't happen so throw an
@@ -1119,7 +1139,8 @@ simpl_top(I, Code, Options) ->
 simpl_top(0, I, Code, _Options) ->
     code_error({optimizer_out_of_fuel, I, Code});
 simpl_top(Fuel, I, Code, Options) ->
-    apply_rules(Fuel, rules(), I, Code, Options).
+    Rules = [R || R = {Rule, _} <- rules(), proplists:get_value(Rule, Options, true)],
+    apply_rules(Fuel, Rules, I, Code, Options).
 
 apply_rules(Fuel, Rules, I, Code, Options) ->
     Cons = fun(X, Xs) -> simpl_top(Fuel - 1, X, Xs, Options) end,
@@ -1146,29 +1167,29 @@ apply_rules_once([{RName, Rule} | Rules], I, Code) ->
 -define(RULE(Name), {Name, fun Name/2}).
 
 merge_rules() ->
-    [?RULE(r_push_consume),
-     ?RULE(r_one_shot_var),
-     ?RULE(r_write_to_dead_var),
-     ?RULE(r_inline_switch_target)
+    [?RULE(optimize_push_consume),
+     ?RULE(optimize_one_shot_var),
+     ?RULE(optimize_write_to_dead_var),
+     ?RULE(optimize_inline_switch_target)
     ].
 
 rules() ->
     merge_rules() ++
-    [?RULE(r_swap_push),
-     ?RULE(r_swap_pop),
-     ?RULE(r_swap_write),
-     ?RULE(r_constant_propagation),
-     ?RULE(r_prune_impossible_branches),
-     ?RULE(r_single_successful_branch),
-     ?RULE(r_inline_store),
-     ?RULE(r_float_switch_body)
+    [?RULE(optimize_swap_push),
+     ?RULE(optimize_swap_pop),
+     ?RULE(optimize_swap_write),
+     ?RULE(optimize_constant_propagation),
+     ?RULE(optimize_prune_impossible_branches),
+     ?RULE(optimize_single_successful_branch),
+     ?RULE(optimize_inline_store),
+     ?RULE(optimize_float_switch_body)
     ].
 
 %% Removing pushes that are immediately consumed.
-r_push_consume({i, Ann1, {'STORE', ?a, A}}, Code) ->
+optimize_push_consume({i, Ann1, {'STORE', ?a, A}}, Code) ->
     inline_push(Ann1, A, 0, Code, []);
 %% Writing directly to memory instead of going through the accumulator.
-r_push_consume({i, Ann1, I}, [{i, Ann2, {'STORE', R, ?a}} | Code]) ->
+optimize_push_consume({i, Ann1, I}, [{i, Ann2, {'STORE', R, ?a}} | Code]) ->
     IsPush =
         case op_view(I) of
             {_, ?a, _} -> true;
@@ -1180,7 +1201,7 @@ r_push_consume({i, Ann1, I}, [{i, Ann2, {'STORE', R, ?a}} | Code]) ->
         end,
     if IsPush -> {[{i, merge_ann(Ann1, Ann2), setelement(2, I, R)}], Code};
        true   -> false end;
-r_push_consume(_, _) -> false.
+optimize_push_consume(_, _) -> false.
 
 inline_push(Ann, Arg, Stack, [{i, _, switch_body} = AI | Code], Acc) ->
     {AI1, {i, Ann1, _}} = swap_instrs({i, Ann, {'STORE', ?a, Arg}}, AI),
@@ -1213,7 +1234,7 @@ split_stack_arg(N, [A | As], Acc) ->
     split_stack_arg(N1, As, [A | Acc]).
 
 %% Move PUSHes past non-stack instructions.
-r_swap_push(Push = {i, _, PushI}, [I | Code]) ->
+optimize_swap_push(Push = {i, _, PushI}, [I | Code]) ->
     case op_view(PushI) of
         {_, ?a, _} ->
             case independent(Push, I) of
@@ -1224,10 +1245,10 @@ r_swap_push(Push = {i, _, PushI}, [I | Code]) ->
             end;
         _ -> false
     end;
-r_swap_push(_, _) -> false.
+optimize_swap_push(_, _) -> false.
 
 %% Move non-stack instruction past POPs.
-r_swap_pop(IA = {i, _, I}, [JA = {i, _, J} | Code]) ->
+optimize_swap_pop(IA = {i, _, I}, [JA = {i, _, J} | Code]) ->
     case independent(IA, JA) of
         true ->
             case {op_view(I), op_view(J)} of
@@ -1235,7 +1256,7 @@ r_swap_pop(IA = {i, _, I}, [JA = {i, _, J} | Code]) ->
                 {_, false} -> false;
                 {{_, IR, IAs}, {_, RJ, JAs}} ->
                     NonStackI = not lists:member(?a, [IR | IAs]),
-                    %% RJ /= ?a to not conflict with r_swap_push
+                    %% RJ /= ?a to not conflict with optimize_swap_push
                     PopJ      = RJ /= ?a andalso lists:member(?a, JAs),
                     case NonStackI andalso PopJ of
                         false -> false;
@@ -1246,22 +1267,22 @@ r_swap_pop(IA = {i, _, I}, [JA = {i, _, J} | Code]) ->
             end;
         false -> false
     end;
-r_swap_pop(_, _) -> false.
+optimize_swap_pop(_, _) -> false.
 
 %% Match up writes to variables with instructions further down.
-r_swap_write(I = {i, _, _}, [J | Code]) ->
+optimize_swap_write(I = {i, _, _}, [J | Code]) ->
     case {var_writes(I), independent(I, J)} of
         {[_], true} ->
             {J1, I1} = swap_instrs(I, J),
-            r_swap_write([J1], I1, Code);
+            optimize_swap_write([J1], I1, Code);
         _ -> false
     end;
-r_swap_write(_, _) -> false.
+optimize_swap_write(_, _) -> false.
 
-r_swap_write(Pre, I, [{i, _, switch_body} = J | Code]) ->
+optimize_swap_write(Pre, I, [{i, _, switch_body} = J | Code]) ->
     {J1, I1} = swap_instrs(I, J),
-    r_swap_write([J1 | Pre], I1, Code);
-r_swap_write(Pre, I, Code0 = [J | Code]) ->
+    optimize_swap_write([J1 | Pre], I1, Code);
+optimize_swap_write(Pre, I, Code0 = [J | Code]) ->
     case apply_rules_once(merge_rules(), I, Code0) of
         {_Rule, New, Rest} ->
             {lists:reverse(Pre) ++ New, Rest};
@@ -1270,27 +1291,27 @@ r_swap_write(Pre, I, Code0 = [J | Code]) ->
                 false -> false;
                 true  ->
                     {J1, I1} = swap_instrs(I, J),
-                    r_swap_write([J1 | Pre], I1, Code)
+                    optimize_swap_write([J1 | Pre], I1, Code)
             end
     end;
-r_swap_write(_, _, _) -> false.
+optimize_swap_write(_, _, _) -> false.
 
 %% Precompute instructions with known values
-r_constant_propagation(Cons = {i, Ann1, {'CONS', R, X, Xs}}, [{i, Ann, {'IS_NIL', S, R}} | Code]) ->
+optimize_constant_propagation(Cons = {i, Ann1, {'CONS', R, X, Xs}}, [{i, Ann, {'IS_NIL', S, R}} | Code]) ->
     Store = {i, Ann, {'STORE', S, ?i(false)}},
     Cons1 = case R of
                 ?a -> {i, Ann1, {'CONS', ?void, X, Xs}};
                 _  -> Cons
             end,
     {[Cons1, Store], Code};
-r_constant_propagation(Nil = {i, Ann1, {'NIL', R}}, [{i, Ann, {'IS_NIL', S, R}} | Code]) ->
+optimize_constant_propagation(Nil = {i, Ann1, {'NIL', R}}, [{i, Ann, {'IS_NIL', S, R}} | Code]) ->
     Store = {i, Ann, {'STORE', S, ?i(true)}},
     Nil1 = case R of
                ?a -> {i, Ann1, {'NIL', ?void}};
                _  -> Nil
            end,
     {[Nil1, Store], Code};
-r_constant_propagation({i, Ann, I}, Code) ->
+optimize_constant_propagation({i, Ann, I}, Code) ->
     case op_view(I) of
         false -> false;
         {Op, R, As} ->
@@ -1304,7 +1325,7 @@ r_constant_propagation({i, Ann, I}, Code) ->
                     end
             end
     end;
-r_constant_propagation(_, _) -> false.
+optimize_constant_propagation(_, _) -> false.
 
 eval_op('ADD', [X, Y]) when is_integer(X), is_integer(Y) -> X + Y;
 eval_op('SUB', [X, Y]) when is_integer(X), is_integer(Y) -> X - Y;
@@ -1323,12 +1344,12 @@ eval_op('NOT', [false]) -> true;
 eval_op(_, _)           -> no_eval.   %% TODO: bits?
 
 %% Prune impossible branches from switches
-r_prune_impossible_branches({switch, ?i(V), Type, Alts, missing}, Code) ->
+optimize_prune_impossible_branches({switch, ?i(V), Type, Alts, missing}, Code) ->
     case pick_branch(Type, V, Alts) of
         false -> false;
         Alt   -> {Alt, Code}
     end;
-r_prune_impossible_branches({switch, ?i(V), boolean, [False, True] = Alts, Def}, Code) when V == true; V == false ->
+optimize_prune_impossible_branches({switch, ?i(V), boolean, [False, True] = Alts, Def}, Code) when V == true; V == false ->
     Alts1 = [if V -> missing; true -> False   end,
              if V -> True;    true -> missing end],
     case Alts == Alts1 of
@@ -1339,7 +1360,7 @@ r_prune_impossible_branches({switch, ?i(V), boolean, [False, True] = Alts, Def},
                 _                  -> {[{switch, ?i(V), boolean, Alts1, Def}], Code}
             end
     end;
-r_prune_impossible_branches(Variant = {i, _, {'VARIANT', R, ?i(_), ?i(Tag), ?i(_)}},
+optimize_prune_impossible_branches(Variant = {i, _, {'VARIANT', R, ?i(_), ?i(Tag), ?i(_)}},
                             [{switch, R, Type = {variant, _}, Alts, missing} | Code]) when is_integer(Tag) ->
     case {R, lists:nth(Tag + 1, Alts)} of
         {_, missing} ->
@@ -1355,7 +1376,7 @@ r_prune_impossible_branches(Variant = {i, _, {'VARIANT', R, ?i(_), ?i(Tag), ?i(_
                 false -> {Alt, Code}
             end
     end;
-r_prune_impossible_branches(_, _) -> false.
+optimize_prune_impossible_branches(_, _) -> false.
 
 pick_branch(boolean, V, [False, True]) when V == true; V == false ->
     Alt = if V -> True; true -> False end,
@@ -1368,7 +1389,7 @@ pick_branch(_Type, _V, _Alts) ->
 
 %% If there's a single branch that doesn't abort we can push the code for that
 %% out of the switch.
-r_single_successful_branch({switch, R, Type, Alts, Def}, Code) ->
+optimize_single_successful_branch({switch, R, Type, Alts, Def}, Code) ->
     case push_code_out_of_switch([Def | Alts]) of
         {_, none} -> false;
         {_, many} -> false;
@@ -1376,7 +1397,7 @@ r_single_successful_branch({switch, R, Type, Alts, Def}, Code) ->
         {[Def1 | Alts1], PushedOut} ->
             {[{switch, R, Type, Alts1, Def1} | PushedOut], Code}
     end;
-r_single_successful_branch(_, _) -> false.
+optimize_single_successful_branch(_, _) -> false.
 
 push_code_out_of_switch([]) -> {[], none};
 push_code_out_of_switch([Alt | Alts]) ->
@@ -1409,12 +1430,10 @@ does_abort({i, _, {'EXIT', _}}) -> true;
 does_abort(missing) -> true;
 does_abort({switch, _, _, Alts, Def}) ->
     lists:all(fun does_abort/1, [Def | Alts]);
-does_abort({loop, Init, _, Expr, _, _}) ->
-    does_abort(Init) orelse does_abort(Expr);
 does_abort(_) -> false.
 
 %% STORE R A, SWITCH R --> SWITCH A
-r_inline_switch_target({i, Ann, {'STORE', R, A}}, [{switch, R, Type, Alts, Def} | Code]) ->
+optimize_inline_switch_target({i, Ann, {'STORE', R, A}}, [{switch, R, Type, Alts, Def} | Code]) ->
     Ann1   =
         case is_reg(A) of
             true  -> Ann#{ live_out := ordsets:add_element(A, maps:get(live_out, Ann)) };
@@ -1433,18 +1452,18 @@ r_inline_switch_target({i, Ann, {'STORE', R, A}}, [{switch, R, Type, Alts, Def}
             end;
         _        -> false %% impossible
     end;
-r_inline_switch_target(_, _) -> false.
+optimize_inline_switch_target(_, _) -> false.
 
 %% Float switch-body to closest switch
-r_float_switch_body(I = {i, _, _}, [J = {i, _, switch_body} | Code]) ->
+optimize_float_switch_body(I = {i, _, _}, [J = {i, _, switch_body} | Code]) ->
     {J1, I1} = swap_instrs(I, J),
     {[], [J1, I1 | Code]};
-r_float_switch_body(_, _) -> false.
+optimize_float_switch_body(_, _) -> false.
 
 %% Inline stores
-r_inline_store({i, _, {'STORE', R, R}}, Code) ->
+optimize_inline_store({i, _, {'STORE', R, R}}, Code) ->
     {[], Code};
-r_inline_store(I = {i, _, {'STORE', R = {var, _}, A}}, Code) ->
+optimize_inline_store(I = {i, _, {'STORE', R = {var, _}, A}}, Code) ->
     %% Not when A is var unless updating the annotations properly.
     Inline = case A of
                  {arg, _}   -> true;
@@ -1452,13 +1471,13 @@ r_inline_store(I = {i, _, {'STORE', R = {var, _}, A}}, Code) ->
                  {store, _} -> true;
                  _          -> false
              end,
-    if Inline -> r_inline_store([I], false, R, A, Code);
+    if Inline -> optimize_inline_store([I], false, R, A, Code);
        true   -> false end;
-r_inline_store(_, _) -> false.
+optimize_inline_store(_, _) -> false.
 
-r_inline_store(Acc, Progress, R, A, [I = {i, _, switch_body} | Code]) ->
-    r_inline_store([I | Acc], Progress, R, A, Code);
-r_inline_store(Acc, Progress, R, A, [{i, Ann, I} | Code]) ->
+optimize_inline_store(Acc, Progress, R, A, [I = {i, _, switch_body} | Code]) ->
+    optimize_inline_store([I | Acc], Progress, R, A, Code);
+optimize_inline_store(Acc, Progress, R, A, [{i, Ann, I} | Code]) ->
     #{ write := W } = attributes(I),
     Inl = fun(X) when X == R -> A; (X) -> X end,
     case live_in(R, Ann) of
@@ -1478,14 +1497,14 @@ r_inline_store(Acc, Progress, R, A, [{i, Ann, I} | Code]) ->
             case lists:member(W, [R, A]) of
                 true when Progress1 -> {lists:reverse(Acc1), Code};
                 true                -> false;
-                false               -> r_inline_store(Acc1, Progress1, R, A, Code)
+                false               -> optimize_inline_store(Acc1, Progress1, R, A, Code)
             end
     end;
-r_inline_store(Acc, true, _, _, Code) -> {lists:reverse(Acc), Code};
-r_inline_store(_, false, _, _, _) -> false.
+optimize_inline_store(Acc, true, _, _, Code) -> {lists:reverse(Acc), Code};
+optimize_inline_store(_, false, _, _, _) -> false.
 
 %% Shortcut write followed by final read
-r_one_shot_var({i, Ann1, I}, [{i, Ann2, J} | Code]) ->
+optimize_one_shot_var({i, Ann1, I}, [{i, Ann2, J} | Code]) ->
     case op_view(I) of
         {Op, R = {var, _}, As} ->
             Copy = case J of
@@ -1499,11 +1518,11 @@ r_one_shot_var({i, Ann1, I}, [{i, Ann2, J} | Code]) ->
             end;
         _ -> false
     end;
-r_one_shot_var(_, _) -> false.
+optimize_one_shot_var(_, _) -> false.
 
 %% Remove writes to dead variables
-r_write_to_dead_var({i, _, {'STORE', ?void, ?a}}, _) -> false; %% Avoid looping
-r_write_to_dead_var({i, Ann, I}, Code) ->
+optimize_write_to_dead_var({i, _, {'STORE', ?void, ?a}}, _) -> false; %% Avoid looping
+optimize_write_to_dead_var({i, Ann, I}, Code) ->
     #{ pure := Pure } = attributes(I),
     case op_view(I) of
         {_Op, R, As} when R /= ?a, Pure ->
@@ -1516,9 +1535,10 @@ r_write_to_dead_var({i, Ann, I}, Code) ->
             end;
         _ -> false
     end;
-r_write_to_dead_var(_, _) -> false.
+optimize_write_to_dead_var(_, _) -> false.
 
 op_view({'ABORT', R}) -> {'ABORT', none, [R]};
+op_view({'EXIT', R}) -> {'EXIT', none, [R]};
 op_view(T) when is_tuple(T) ->
     [Op, R | As] = tuple_to_list(T),
     CheckReads = fun(Rs, X) -> case [] == Rs -- [dst, src] of true -> X; false -> false end end,
@@ -1538,8 +1558,6 @@ from_op_view(Op, R, As) -> list_to_tuple([Op, R | As]).
                 (missing)    -> missing.
 unannotate({switch, Arg, Type, Alts, Def}) ->
     [{switch, Arg, Type, [unannotate(A) || A <- Alts], unannotate(Def)}];
-unannotate({loop, Init, It, Body, BRef, CRef}) ->
-    [{loop, unannotate(Init), It, unannotate(Body), BRef, CRef}];
 unannotate(missing) -> missing;
 unannotate(Code) when is_list(Code) ->
     lists:flatmap(fun unannotate/1, Code);
@@ -1556,8 +1574,6 @@ desugar({'STORE', ?a, A})       -> [aeb_fate_ops:push(desugar_arg(A))];
 desugar({'STORE', R, ?a})       -> [aeb_fate_ops:pop(desugar_arg(R))];
 desugar({switch, Arg, Type, Alts, Def}) ->
     [{switch, desugar_arg(Arg), Type, [desugar(A) || A <- Alts], desugar(Def)}];
-desugar({loop, Init, Var, Expr, ContRef, BreakRef}) ->
-    [{loop, desugar(Init), Var, desugar(Expr), ContRef, BreakRef}];
 desugar(missing) -> missing;
 desugar(Code) when is_list(Code) ->
     lists:flatmap(fun desugar/1, Code);
@@ -1604,7 +1620,7 @@ bb(_Name, Code) ->
 -type bb()     :: {bbref(), bcode()}.
 -type bcode()  :: [binstr()].
 -type binstr() :: {jump, bbref()}
-                | {jumpif, term(), bbref()}
+                | {jumpif, bbref()}
                 | tuple().   %% FATE instruction
 
 -spec blocks(scode()) -> [bb()].
@@ -1618,29 +1634,25 @@ blocks([], Acc) ->
 blocks([Blk | Blocks], Acc) ->
     block(Blk, [], Blocks, Acc).
 
-fresh_block(C, Ca) ->
-    R = make_ref(),
-    {R, [#blk{ref = R, code = C, catchall = Ca}]}.
-
 -spec block(#blk{}, bcode(), [#blk{}], [bb()]) -> [bb()].
 block(#blk{ref = Ref, code = []}, CodeAcc, Blocks, BlockAcc) ->
     blocks(Blocks, [{Ref, lists:reverse(CodeAcc)} | BlockAcc]);
-block(Blk = #blk{code = [{loop, Init, _, Expr, ContRef, BreakRef} | Code], catchall = Catchall}, Acc, Blocks, BlockAcc) ->
-    LoopBlock = #blk{ref = ContRef, code = Expr, catchall = none},
-    BreakBlock = #blk{ref = BreakRef, code = Code, catchall = Catchall},
-    block(Blk#blk{code = Init}, Acc, [LoopBlock, BreakBlock | Blocks], BlockAcc);
 block(Blk = #blk{code = [switch_body | Code]}, Acc, Blocks, BlockAcc) ->
     %% Reached the body of a switch. Clear catchall ref.
     block(Blk#blk{code = Code, catchall = none}, Acc, Blocks, BlockAcc);
 block(Blk = #blk{code     = [{switch, Arg, Type, Alts, Default} | Code],
                  catchall = Catchall}, Acc, Blocks, BlockAcc) ->
-    {RestRef, RestBlk} = fresh_block(Code, Catchall),
+    FreshBlk = fun(C, Ca) ->
+                   R = make_ref(),
+                   {R, [#blk{ref = R, code = C, catchall = Ca}]}
+               end,
+    {RestRef, RestBlk} = FreshBlk(Code, Catchall),
     {DefRef, DefBlk} =
         case Default of
             missing when Catchall == none ->
-                fresh_block([aeb_fate_ops:abort(?i(<<"Incomplete patterns">>))], none);
+                FreshBlk([aeb_fate_ops:abort(?i(<<"Incomplete patterns">>))], none);
             missing -> {Catchall, []};
-            _       -> fresh_block(Default ++ [{jump, RestRef}], Catchall)
+            _       -> FreshBlk(Default ++ [{jump, RestRef}], Catchall)
                        %% ^ fall-through to the outer catchall
         end,
     %% If we don't generate a switch, we need to pop the argument if on the stack.
@@ -1652,7 +1664,7 @@ block(Blk = #blk{code     = [{switch, Arg, Type, Alts, Default} | Code],
                 {ThenRef, ThenBlk} =
                     case TrueCode of
                         missing -> {DefRef, []};
-                        _       -> fresh_block(TrueCode ++ [{jump, RestRef}], DefRef)
+                        _       -> FreshBlk(TrueCode ++ [{jump, RestRef}], DefRef)
                     end,
                 ElseCode =
                     case FalseCode of
@@ -1687,7 +1699,7 @@ block(Blk = #blk{code     = [{switch, Arg, Type, Alts, Default} | Code],
                     true  -> {Blk#blk{code = Pop ++ [{jump, DefRef}]}, [], []};
                     false ->
                         MkBlk = fun(missing) -> {DefRef, []};
-                                   (ACode)   -> fresh_block(ACode ++ [{jump, RestRef}], DefRef)
+                                   (ACode)   -> FreshBlk(ACode ++ [{jump, RestRef}], DefRef)
                                 end,
                         {AltRefs, AltBs} = lists:unzip(lists:map(MkBlk, Alts)),
                         {Blk#blk{code = []}, [{switch, Arg, AltRefs}], lists:append(AltBs)}
@@ -1703,7 +1715,7 @@ block(Blk = #blk{code = [I | Code]}, Acc, Blocks, BlockAcc) ->
 optimize_blocks(Blocks) ->
     %% We need to look at the last instruction a lot, so reverse all blocks.
     Rev       = fun(Bs) -> [ {Ref, lists:reverse(Code)} || {Ref, Code} <- Bs ] end,
-    RBlocks   =  [{Ref, crop_jumps(Code)} || {Ref, Code} <- Blocks],
+    RBlocks   = Rev(Blocks),
     RBlockMap = maps:from_list(RBlocks),
     RBlocks1  = reorder_blocks(RBlocks, []),
     RBlocks2  = [ {Ref, inline_block(RBlockMap, Ref, Code)} || {Ref, Code} <- RBlocks1 ],
@@ -1785,18 +1797,6 @@ tweak_returns(['RETURN' | Code = [{'EXIT', _} | _]])   -> Code;
 tweak_returns(['RETURN' | Code = [loop | _]])          -> Code;
 tweak_returns(Code) -> Code.
 
-%% -- Remove instructions that appear after jumps. Returns reversed code.
-%% This is useful for example when bb emitter adds continuation jumps
-%% for switch expressions, but some of the branches
-crop_jumps(Code) ->
-    crop_jumps(Code, []).
-crop_jumps([], Acc) ->
-    Acc;
-crop_jumps([I = {jump, _}|_], Acc) ->
-    [I|Acc];
-crop_jumps([I|Code], Acc) ->
-    crop_jumps(Code, [I|Acc]).
-
 %% -- Split basic blocks at CALL instructions --
 %%  Calls can only return to a new basic block. Also splits at JUMPIF instructions.
 

src/aeso_parser.erl

@@ -359,9 +359,12 @@ exprAtom() ->
         , ?RULE(tok('['), Expr, binop('..'), Expr, tok(']'), _3(_2, _4))
         , ?RULE(keyword('('), comma_sep(Expr), tok(')'), tuple_e(_1, _2))
         , letpat()
+        , hole()
         ])
     end).
 
+hole() -> ?RULE(token('???'), {id, get_ann(_1), "???"}).
+
 comprehension_exp() ->
     ?LAZY_P(choice(
       [ comprehension_bind()

src/aeso_pretty.erl

@@ -261,6 +261,8 @@ type(Type, Options) ->
     with_options(Options, fun() -> type(Type) end).
 
 -spec type(aeso_syntax:type()) -> doc().
+type(F = {fun_t, _, _, var_args, _}) ->
+    type(setelement(4, F, [var_args]));
 type({fun_t, _, Named, Args, Ret}) ->
     follow(hsep(args_type(Named ++ Args), text("=>")), type(Ret));
 type({type_sig, _, Named, Args, Ret}) ->
@@ -288,7 +290,9 @@ type(T = {id, _, _})   -> name(T);
 type(T = {qid, _, _})  -> name(T);
 type(T = {con, _, _})  -> name(T);
 type(T = {qcon, _, _}) -> name(T);
-type(T = {tvar, _, _}) -> name(T).
+type(T = {tvar, _, _}) -> name(T);
+
+type(var_args) -> text("var_args").
 
 -spec args_type([aeso_syntax:type()]) -> doc().
 args_type(Args) ->
@@ -430,6 +434,7 @@ lc_bind(Let) ->
 bin_prec('..')   -> {  0,   0,   0};  %% Always printed inside '[ ]'
 bin_prec('=')    -> {  0,   0,   0};  %% Always printed inside '[ ]'
 bin_prec('@')    -> {  0,   0,   0};  %% Only in error messages
+bin_prec('|>')   -> {150, 150, 200};
 bin_prec('||')   -> {200, 300, 200};
 bin_prec('&&')   -> {300, 400, 300};
 bin_prec('<')    -> {400, 500, 500};

src/aeso_syntax.erl

@@ -13,7 +13,7 @@
 -export_type([ann_line/0, ann_col/0, ann_origin/0, ann_format/0, ann/0]).
 -export_type([name/0, id/0, con/0, qid/0, qcon/0, tvar/0, op/0]).
 -export_type([bin_op/0, un_op/0]).
--export_type([decl/0, letbind/0, typedef/0, pragma/0]).
+-export_type([decl/0, letbind/0, typedef/0, pragma/0, fundecl/0]).
 -export_type([arg/0, field_t/0, constructor_t/0, named_arg_t/0]).
 -export_type([type/0, constant/0, expr/0, arg_expr/0, field/1, stmt/0, alt/0, lvalue/0, elim/0, pat/0]).
 -export_type([ast/0]).
@@ -26,7 +26,7 @@
 -type ann_format() :: '?:' | hex | infix | prefix | elif.
 
 -type ann() :: [ {line, ann_line()} | {col, ann_col()} | {format, ann_format()} | {origin, ann_origin()}
-               | stateful | private | payable | main | interface].
+               | stateful | private | payable | main | interface | entrypoint].
 
 -type name() :: string().
 -type id()   :: {id,   ann(), name()}.
@@ -42,6 +42,7 @@
               | {contract_child, ann(), con(), [con()], [decl()]}
               | {contract_interface, ann(), con(), [con()], [decl()]}
               | {namespace, ann(), con(), [decl()]}
+              | {include, ann(), {string, ann(), string()}}
               | {pragma, ann(), pragma()}
               | {type_decl, ann(), id(), [tvar()]} % Only for error msgs
               | {type_def, ann(), id(), [tvar()], typedef()}
@@ -105,7 +106,7 @@
 
 -type bin_op() :: '+' | '-' | '*' | '/' | mod | '^'
                 | '++' | '::' | '<' | '>' | '=<' | '>=' | '==' | '!='
-                | '||' | '&&' | '..'.
+                | '||' | '&&' | '..' | '|>'.
 -type un_op() :: '-' | '!'.
 
 -type expr()

src/aesophia.app.src

@@ -1,6 +1,6 @@
 {application, aesophia,
  [{description, "Compiler for Aeternity Sophia language"},
-  {vsn, "6.1.0"},
+  {vsn, "7.1.0"},
   {registered, []},
   {applications,
    [kernel,

test/aeso_aci_tests.erl

@@ -21,7 +21,7 @@ test_cases(1) ->
 		 "  payable stateful entrypoint a(i : int) = i+1\n">>,
     MapACI = #{contract =>
 		   #{name => <<"C">>,
-		     type_defs => [],
+		     typedefs => [],
          payable => true,
          kind => contract_main,
 		     functions =>
@@ -43,7 +43,7 @@ test_cases(2) ->
     MapACI = #{contract =>
                    #{name => <<"C">>, payable => false,
                      kind => contract_main,
-                     type_defs =>
+                     typedefs =>
                          [#{name => <<"allan">>,
                             typedef => <<"int">>,
                             vars => []}],
@@ -76,7 +76,7 @@ test_cases(3) ->
 		     name => <<"C">>, payable => false, kind => contract_main,
          event => #{variant => [#{<<"SingleEventDefined">> => []}]},
          state => <<"unit">>,
-		     type_defs =>
+		     typedefs =>
              [#{name => <<"bert">>,
                 typedef =>
                     #{variant =>
@@ -127,7 +127,7 @@ check_stub(Stub, Options) ->
         Ast ->
             try
                 %% io:format("AST: ~120p\n", [Ast]),
-                aeso_ast_infer_types:infer(Ast, [])
+                aeso_ast_infer_types:infer(Ast, [no_code])
             catch throw:{type_errors, TE} ->
                 io:format("Type error:\n~s\n", [TE]),
                 error(TE);

test/aeso_calldata_tests.erl

@@ -29,7 +29,7 @@ calldata_aci_test_() ->
      [ {"Testing " ++ ContractName ++ " contract calling " ++ Fun,
         fun() ->
            ContractString       = aeso_test_utils:read_contract(ContractName),
-           {ok, ContractACIBin} = aeso_aci:contract_interface(string, ContractString),
+           {ok, ContractACIBin} = aeso_aci:contract_interface(string, ContractString, [no_code]),
            ContractACI = binary_to_list(ContractACIBin),
            io:format("ACI:\n~s\n", [ContractACIBin]),
            FateExprs = ast_exprs(ContractACI, Fun, Args),

test/aeso_compiler_tests.erl

@@ -45,12 +45,6 @@ simple_compile_test_() ->
            check_errors(ExpectedErrors, Errors)
        end} ||
            {ContractName, ExpectedErrors} <- failing_contracts() ] ++
-    [ {"Testing code generation error messages of " ++ ContractName,
-       fun() ->
-               Errors = compile(ContractName),
-               check_errors([ExpectedError], Errors)
-       end} ||
-           {ContractName, ExpectedError} <- failing_code_gen_contracts()] ++
     [ {"Testing include with explicit files",
        fun() ->
            FileSystem = maps:from_list(
@@ -208,6 +202,25 @@ compilable_contracts() ->
      "polymorphism_contract_interface_extensions",
      "polymorphism_contract_interface_same_decl_multi_interface",
      "polymorphism_contract_interface_same_name_same_type",
+     "polymorphism_variance_switching_chain_create",
+     "polymorphism_variance_switching_void_supertype",
+     "polymorphism_variance_switching_unify_with_interface_decls",
+     "polymorphism_preserve_or_add_payable_contract",
+     "polymorphism_preserve_or_add_payable_entrypoint",
+     "polymorphism_preserve_or_remove_stateful_entrypoint",
+     "missing_init_fun_state_unit",
+     "complex_compare_leq",
+     "complex_compare",
+     "higher_order_compare",
+     "higher_order_map_keys",
+     "higher_order_state",
+     "polymorphic_compare",
+     "polymorphic_entrypoint",
+     "polymorphic_entrypoint_return",
+     "polymorphic_map_keys",
+     "unapplied_contract_call",
+     "unapplied_named_arg_builtin",
+     "resolve_field_constraint_by_arity",
      "test" % Custom general-purpose test file. Keep it last on the list.
     ].
 
@@ -289,34 +302,26 @@ failing_contracts() ->
 
     %% Type errors
     , ?TYPE_ERROR(name_clash,
-       [<<?Pos(14, 3)
+       [<<?Pos(4, 3)
+          "Duplicate definitions of `double_def` at\n"
+          "  - line 3, column 3\n"
+          "  - line 4, column 3">>,
+        <<?Pos(7, 3)
           "Duplicate definitions of `abort` at\n"
           "  - (builtin location)\n"
-          "  - line 14, column 3">>,
-        <<?Pos(15, 3)
+          "  - line 7, column 3">>,
+        <<?Pos(8, 3)
           "Duplicate definitions of `require` at\n"
           "  - (builtin location)\n"
-          "  - line 15, column 3">>,
-        <<?Pos(11, 3)
-          "Duplicate definitions of `double_def` at\n"
-          "  - line 10, column 3\n"
-          "  - line 11, column 3">>,
-        <<?Pos(5, 3)
-          "Duplicate definitions of `double_proto` at\n"
-          "  - line 4, column 3\n"
-          "  - line 5, column 3">>,
-        <<?Pos(8, 3)
-          "Duplicate definitions of `proto_and_def` at\n"
-          "  - line 7, column 3\n"
           "  - line 8, column 3">>,
-        <<?Pos(16, 3)
+        <<?Pos(9, 3)
           "Duplicate definitions of `put` at\n"
           "  - (builtin location)\n"
-          "  - line 16, column 3">>,
-        <<?Pos(17, 3)
+          "  - line 9, column 3">>,
+        <<?Pos(10, 3)
           "Duplicate definitions of `state` at\n"
           "  - (builtin location)\n"
-          "  - line 17, column 3">>])
+          "  - line 10, column 3">>])
     , ?TYPE_ERROR(type_errors,
        [<<?Pos(17, 23)
           "Unbound variable `zz`">>,
@@ -732,10 +737,22 @@ failing_contracts() ->
                      "Conflicting updates for field 'foo'">>])
     , ?TYPE_ERROR(factories_type_errors,
                   [<<?Pos(10,18)
-                    "Chain.clone requires `ref` named argument of contract type.">>,
+                     "Chain.clone requires `ref` named argument of contract type.">>,
                    <<?Pos(11,18)
-                     "Cannot unify `(gas : int, value : int, protected : bool) => if(protected, option(void), void)` and `(gas : int, value : int, protected : bool, int, bool) => 'b`\n"
-                     "when checking contract construction of type\n  (gas : int, value : int, protected : bool) =>\n    if(protected, option(void), void) (at line 11, column 18)\nagainst the expected type\n  (gas : int, value : int, protected : bool, int, bool) => 'b">>,
+                     "Cannot unify `(gas : int, value : int, protected : bool) => if(protected, option(void), void)` and `(gas : int, value : int, protected : bool, int, bool) => if(protected, option(void), void)`\n"
+                     "when checking contract construction of type\n"
+                     "  (gas : int, value : int, protected : bool) =>\n"
+                     "    if(protected, option(void), void) (at line 11, column 18)\n"
+                     "against the expected type\n"
+                     "  (gas : int, value : int, protected : bool, int, bool) =>\n"
+                     "    if(protected, option(void), void)">>,
+                   <<?Pos(11,18)
+                     "Cannot unify `Bakoom` and `Kaboom`\n"
+                     "when checking that contract construction of type\n"
+                     "  Bakoom\n"
+                     "arising from resolution of variadic function `Chain.clone`\n"
+                     "matches the expected type\n"
+                     "  Kaboom">>,
                    <<?Pos(12,37)
                      "Cannot unify `int` and `bool`\n"
                      "when checking named argument `gas : int` against inferred type `bool`">>,
@@ -848,25 +865,25 @@ failing_contracts() ->
                      "Trying to implement or extend an undefined interface `Z`">>
                   ])
     , ?TYPE_ERROR(polymorphism_contract_interface_same_name_different_type,
-                  [<<?Pos(4,20)
-                     "Unimplemented function `f` from the interface `I1` in the contract `I2`">>])
+                  [<<?Pos(9,5)
+                     "Duplicate definitions of `f` at\n"
+                     "  - line 8, column 5\n"
+                     "  - line 9, column 5">>])
     , ?TYPE_ERROR(polymorphism_contract_missing_implementation,
                   [<<?Pos(4,20)
-                     "Unimplemented function `f` from the interface `I1` in the contract `I2`">>
+                     "Unimplemented entrypoint `f` from the interface `I1` in the contract `I2`">>
                   ])
     , ?TYPE_ERROR(polymorphism_contract_same_decl_multi_interface,
                   [<<?Pos(7,10)
-                     "Unimplemented function `f` from the interface `J` in the contract `C`">>
+                     "Both interfaces `I` and `J` implemented by the contract `C` have a function called `f`">>
                   ])
     , ?TYPE_ERROR(polymorphism_contract_undefined_interface,
                   [<<?Pos(1,14)
                      "Trying to implement or extend an undefined interface `I`">>
                   ])
     , ?TYPE_ERROR(polymorphism_contract_same_name_different_type_multi_interface,
-                  [<<?Pos(9,5)
-                     "Duplicate definitions of `f` at\n"
-                     "  - line 8, column 5\n"
-                     "  - line 9, column 5">>
+                  [<<?Pos(7,10)
+                     "Both interfaces `I` and `J` implemented by the contract `C` have a function called `f`">>
                   ])
     , ?TYPE_ERROR(polymorphism_contract_interface_undefined_interface,
                   [<<?Pos(1,24)
@@ -981,7 +998,8 @@ failing_contracts() ->
                      "when checking the type of the pattern `r10 : rec_inv(Animal)` against the expected type `Main.rec_inv(Cat)`">>,
                    <<?Pos(41,13)
                      "Cannot unify `Animal` and `Cat` in a invariant context\n"
-                     "when checking the type of the pattern `r11 : rec_inv(Cat)` against the expected type `Main.rec_inv(Animal)`">>])
+                     "when checking the type of the pattern `r11 : rec_inv(Cat)` against the expected type `Main.rec_inv(Animal)`">>
+                  ])
     , ?TYPE_ERROR(polymorphism_variance_switching_oracles,
                   [<<?Pos(15,13)
                      "Cannot unify `Cat` and `Animal` in a contravariant context\n"
@@ -1024,58 +1042,156 @@ failing_contracts() ->
                      "when checking the type of the pattern `q14 : oracle_query(Cat, Cat)` against the expected type `oracle_query(Animal, Cat)`">>,
                    <<?Pos(44,13)
                      "Cannot unify `Animal` and `Cat` in a covariant context\n"
-                     "when checking the type of the pattern `q15 : oracle_query(Cat, Cat)` against the expected type `oracle_query(Cat, Animal)`">>])
-    ].
-
--define(Path(File), "code_errors/" ??File).
--define(Msg(File, Line, Col, Err), <<?Pos("Code generation", ?Path(File), Line, Col) Err>>).
-
--define(FATE_ERR(File, Line, Col, Err), {?Path(File), ?Msg(File, Line, Col, Err)}).
-
-failing_code_gen_contracts() ->
-    [ ?FATE_ERR(missing_definition, 2, 14,
-            "Missing definition of function 'foo'.")
-    , ?FATE_ERR(higher_order_entrypoint, 2, 20,
-            "The argument\n"
-            "  f : (int) => int\n"
-            "of entrypoint 'apply' has a higher-order (contains function types) type.")
-    , ?FATE_ERR(higher_order_entrypoint_return, 2, 3,
-            "The return type\n"
-            "  (int) => int\n"
-            "of entrypoint 'add' is higher-order (contains function types).")
-    , ?FATE_ERR(missing_init_function, 1, 10,
-            "Missing init function for the contract 'MissingInitFunction'.\n"
-            "The 'init' function can only be omitted if the state type is 'unit'.")
-    , ?FATE_ERR(parameterised_state, 3, 8,
-            "The state type cannot be parameterized.")
-    , ?FATE_ERR(parameterised_event, 3, 12,
-            "The event type cannot be parameterized.")
-    , ?FATE_ERR(polymorphic_aens_resolve, 4, 5,
-            "Invalid return type of AENS.resolve:\n"
-            "  'a\n"
-            "It must be a string or a pubkey type (address, oracle, etc).")
-    , ?FATE_ERR(bad_aens_resolve, 6, 5,
-            "Invalid return type of AENS.resolve:\n"
-            "  list(int)\n"
-            "It must be a string or a pubkey type (address, oracle, etc).")
-    , ?FATE_ERR(polymorphic_query_type, 3, 5,
-            "Invalid oracle type\n"
-            "  oracle('a, 'b)\n"
-            "The query type must not be polymorphic (contain type variables).")
-    , ?FATE_ERR(polymorphic_response_type, 3, 5,
-            "Invalid oracle type\n"
-            "  oracle(string, 'r)\n"
-            "The response type must not be polymorphic (contain type variables).")
-    , ?FATE_ERR(higher_order_query_type, 3, 5,
-            "Invalid oracle type\n"
-            "  oracle((int) => int, string)\n"
-            "The query type must not be higher-order (contain function types).")
-    , ?FATE_ERR(higher_order_response_type, 3, 5,
-            "Invalid oracle type\n"
-            "  oracle(string, (int) => int)\n"
-            "The response type must not be higher-order (contain function types).")
-    , ?FATE_ERR(child_with_decls, 2, 14,
-            "Missing definition of function 'f'.")
+                     "when checking the type of the pattern `q15 : oracle_query(Cat, Cat)` against the expected type `oracle_query(Cat, Animal)`">>
+                  ])
+    , ?TYPE_ERROR(polymorphism_variance_switching_chain_create_fail,
+                  [<<?Pos(9,22)
+                     "I is not implemented.\n"
+                     "when resolving arguments of variadic function `Chain.create`">>,
+                   <<?Pos(10,13)
+                     "Cannot unify `I` and `C` in a covariant context\n"
+                     "when checking the type of the pattern `c2 : C` against the expected type `I`">>,
+                   <<?Pos(10,22)
+                     "I is not implemented.\n"
+                     "when resolving arguments of variadic function `Chain.create`">>,
+                   <<?Pos(11,22)
+                     "I is not implemented.\n"
+                     "when resolving arguments of variadic function `Chain.create`">>
+                  ])
+    , ?TYPE_ERROR(missing_definition,
+                  [<<?Pos(2,14)
+                     "Missing definition of function `foo`">>
+                  ])
+    , ?TYPE_ERROR(child_with_decls,
+                  [<<?Pos(2,14)
+                     "Missing definition of function `f`">>
+                  ])
+    , ?TYPE_ERROR(parameterised_state,
+                  [<<?Pos(3,8)
+                     "The state type cannot be parameterized">>
+                  ])
+    , ?TYPE_ERROR(parameterised_event,
+                  [<<?Pos(3,12)
+                     "The event type cannot be parameterized">>
+                  ])
+    , ?TYPE_ERROR(missing_init_fun_alias_to_type,
+                  [<<?Pos(1,10)
+                     "Missing `init` function for the contract `AliasToType`.\n"
+                     "The `init` function can only be omitted if the state type is `unit`">>
+                  ])
+    , ?TYPE_ERROR(missing_init_fun_alias_to_alias_to_type,
+                  [<<?Pos(1,10)
+                     "Missing `init` function for the contract `AliasToAliasToType`.\n"
+                     "The `init` function can only be omitted if the state type is `unit`">>
+                  ])
+    , ?TYPE_ERROR(higher_order_entrypoint,
+                  [<<?Pos(2,20)
+                     "The argument\n"
+                     "  `f : (int) => int`\n"
+                     "of entrypoint `apply` has a higher-order (contains function types) type">>
+                  ])
+    , ?TYPE_ERROR(higher_order_entrypoint_return,
+                  [<<?Pos(2,3)
+                     "The return type\n"
+                     "  `(int) => int`\n"
+                     "of entrypoint `add` is higher-order (contains function types)">>
+                  ])
+    , ?TYPE_ERROR(polymorphic_aens_resolve,
+                  [<<?Pos(4,5)
+                     "Invalid return type of `AENS.resolve`:\n"
+                     "  `'a`\n"
+                     "It must be a `string` or a pubkey type (`address`, `oracle`, etc)">>
+                  ])
+    , ?TYPE_ERROR(bad_aens_resolve,
+                  [<<?Pos(6,5)
+                     "Invalid return type of `AENS.resolve`:\n"
+                     "  `list(int)`\n"
+                     "It must be a `string` or a pubkey type (`address`, `oracle`, etc)">>
+                  ])
+    , ?TYPE_ERROR(bad_aens_resolve_using,
+                  [<<?Pos(7,5)
+                     "Invalid return type of `AENS.resolve`:\n"
+                     "  `list(int)`\n"
+                     "It must be a `string` or a pubkey type (`address`, `oracle`, etc)">>
+                  ])
+    , ?TYPE_ERROR(polymorphic_query_type,
+                  [<<?Pos(3,5)
+                     "Invalid oracle type\n"
+                     "  `oracle('a, 'b)`\n"
+                     "The query type must not be polymorphic (contain type variables)">>,
+                   <<?Pos(3,5)
+                     "Invalid oracle type\n"
+                     "  `oracle('a, 'b)`\n"
+                     "The response type must not be polymorphic (contain type variables)">>
+                  ])
+    , ?TYPE_ERROR(polymorphic_response_type,
+                  [<<?Pos(3,5)
+                     "Invalid oracle type\n"
+                     "  `oracle(string, 'r)`\n"
+                     "The response type must not be polymorphic (contain type variables)">>
+                  ])
+    , ?TYPE_ERROR(higher_order_query_type,
+                  [<<?Pos(3,5)
+                     "Invalid oracle type\n"
+                     "  `oracle((int) => int, string)`\n"
+                     "The query type must not be higher-order (contain function types)">>
+                  ])
+    , ?TYPE_ERROR(higher_order_response_type,
+                  [<<?Pos(3,5)
+                     "Invalid oracle type\n"
+                     "  `oracle(string, (int) => int)`\n"
+                     "The response type must not be higher-order (contain function types)">>
+                  ])
+    , ?TYPE_ERROR(var_args_unify_let,
+                  [<<?Pos(3,9)
+                     "Cannot infer types for variable argument list.\n"
+                     "when checking the type of the pattern `x : 'a` against the expected type `(gas : int, value : int, protected : bool, ref : 'b, var_args) => 'b`">>
+                  ])
+    , ?TYPE_ERROR(var_args_unify_fun_call,
+                  [<<?Pos(6,5)
+                     "Cannot infer types for variable argument list.\n"
+                     "when checking the application of\n"
+                     "  `g : (() => 'b) => 'b`\n"
+                     "to arguments\n"
+                     "  `Chain.create : (value : int, var_args) => 'c`">>
+                  ])
+    , ?TYPE_ERROR(polymorphism_add_stateful_entrypoint,
+                  [<<?Pos(5,25)
+                     "`f` cannot be stateful because the entrypoint `f` in the interface `I` is not stateful">>
+                  ])
+    , ?TYPE_ERROR(polymorphism_change_entrypoint_to_function,
+                  [<<?Pos(6,14)
+                     "`f` must be declared as an entrypoint instead of a function in order to implement the entrypoint `f` from the interface `I`">>
+                  ])
+    , ?TYPE_ERROR(polymorphism_non_payable_contract_implement_payable,
+                  [<<?Pos(4,10)
+                     "Non-payable contract `C` cannot implement payable interface `I`">>
+                  ])
+    , ?TYPE_ERROR(polymorphism_non_payable_interface_implement_payable,
+                  [<<?Pos(4,20)
+                     "Non-payable interface `H` cannot implement payable interface `I`">>
+                  ])
+    , ?TYPE_ERROR(polymorphism_remove_payable_entrypoint,
+                  [<<?Pos(5,16)
+                     "`f` must be payable because the entrypoint `f` in the interface `I` is payable">>
+                  ])
+    , ?TYPE_ERROR(calling_child_contract_entrypoint,
+                  [<<?Pos(5,20)
+                     "Invalid call to contract entrypoint `F.g`.\n"
+                     "It must be called as `c.g` for some `c : F`.">>])
+    , ?TYPE_ERROR(using_contract_as_namespace,
+                  [<<?Pos(5,3)
+                     "Cannot use undefined namespace F">>])
+    , ?TYPE_ERROR(hole_expression,
+                  [<<?Pos(5,13)
+                     "Found a hole of type `bool`">>,
+                   <<?Pos(6,17)
+                     "Found a hole of type `string`">>,
+                   <<?Pos(9,37)
+                     "Found a hole of type `(int) => int`">>,
+                   <<?Pos(13,20)
+                     "Found a hole of type `'a`">>
+                  ])
     ].
 
 validation_test_() ->

test/contracts/aens.aes

@@ -1,5 +1,7 @@
+contract C = entrypoint init() = ()
+
 // AENS tests
-contract AENSTest =
+main contract AENSTest =
 
   // Name resolution
 
@@ -9,10 +11,19 @@ contract AENSTest =
   stateful entrypoint resolve_string(name : string, key : string) : option(string) =
     AENS.resolve(name, key)
 
+  stateful entrypoint resolve_contract(name : string, key : string) : option(C) =
+    AENS.resolve(name, key)
+
+  stateful entrypoint resolve_oracle(name : string, key : string) : option(oracle(int, int)) =
+    AENS.resolve(name, key)
+
+  stateful entrypoint resolve_oracle_query(name : string, key : string) : option(oracle_query(int, int)) =
+    AENS.resolve(name, key)
+
   // Transactions
 
   stateful entrypoint preclaim(addr  : address,     // Claim on behalf of this account (can be Contract.address)
-                             chash : hash) : unit = // Commitment hash
+                               chash : hash) : unit = // Commitment hash
     AENS.preclaim(addr, chash)
 
   stateful entrypoint signedPreclaim(addr  : address, // Claim on behalf of this account (can be Contract.address)

test/contracts/all_syntax.aes

@@ -80,3 +80,4 @@ contract AllSyntax =
      let sh : shakespeare(shakespeare(int)) =
        {wolfgang = state}
      sh{wolfgang.wolfgang = sh.wolfgang} // comment
+     exit("hope you had fun reading this")

test/contracts/bad_aens_resolve_using.aes

@@ -0,0 +1,9 @@
+contract BadAENSresolve =
+  using AENS
+
+  type t('a) = option(list('a))
+
+  function fail() : t(int) =
+    resolve("foo.aet", "whatever")
+
+  entrypoint main_fun() = ()

test/contracts/calling_child_contract_entrypoint.aes

@@ -0,0 +1,5 @@
+contract F =
+  entrypoint g() = 1
+
+main contract C =
+  entrypoint f() = F.g()

test/contracts/code_errors/missing_init_function.aes

@@ -1,3 +0,0 @@
-contract MissingInitFunction =
-  type state = int * int
-

test/contracts/complex_types.aes

@@ -1,16 +1,7 @@
 
-contract interface Remote =
-  entrypoint up_to       : (int)               => list(int)
-  entrypoint sum         : (list(int))         => int
-  entrypoint some_string : ()                  => string
-  entrypoint pair        : (int, string)       => int * string
-  entrypoint squares     : (int)               => list(int * int)
-  entrypoint filter_some : (list(option(int))) => list(int)
-  entrypoint all_some    : (list(option(int))) => option(list(int))
-
 contract ComplexTypes =
 
-  record state = { worker : Remote }
+  record state = { worker : ComplexTypes }
 
   entrypoint init(worker) = {worker = worker}
 

test/contracts/environment.aes

@@ -1,14 +1,9 @@
 
 // Testing primitives for accessing the block chain environment
-contract interface Interface =
-  entrypoint contract_address : () => address
-  entrypoint call_origin      : () => address
-  entrypoint call_caller      : () => address
-  entrypoint call_value       : () => int
 
 contract Environment =
 
-  record state = {remote : Interface}
+  record state = {remote : Environment}
 
   entrypoint init(remote) = {remote = remote}
 

test/contracts/hole_expression.aes

@@ -0,0 +1,13 @@
+include "List.aes"
+
+contract C =
+    entrypoint f() =
+        let ??? = true
+        let v = ???
+        let q = v == "str"
+        let xs = [1, 2, 3, 4]
+        switch (List.first(List.map(???, xs)))
+            Some(x) => x + 1
+            None    => 0
+
+    function g() = ???

test/contracts/missing_init_fun_alias_to_alias_to_type.aes

@@ -0,0 +1,3 @@
+contract AliasToAliasToType =
+  type alias = int * int
+  type state = alias

test/contracts/missing_init_fun_alias_to_type.aes

@@ -0,0 +1,2 @@
+contract AliasToType =
+  type state = int * int

test/contracts/missing_init_fun_state_unit.aes

@@ -0,0 +1,9 @@
+contract AliasToAliasToUnit =
+  type alias = unit
+  type state = alias
+
+contract AliasToUnit =
+  type state = unit
+
+main contract ImplicitState =
+    type sometype = int

test/contracts/name_clash.aes

@@ -1,12 +1,5 @@
-
 contract NameClash =
 
-  entrypoint double_proto : () => int
-  entrypoint double_proto : () => int
-
-  entrypoint proto_and_def : int => int
-  entrypoint proto_and_def(n) = n + 1
-
   entrypoint double_def(x) = x
   entrypoint double_def(y) = 0
 
@@ -14,4 +7,4 @@ contract NameClash =
   entrypoint abort() : int = 0
   entrypoint require(b, err) = if(b) abort(err)
   entrypoint put(x) = x
-  entrypoint state(x, y) = x + y
+  entrypoint state(x, y) = x + y

test/contracts/polymorphism_add_stateful_entrypoint.aes

@@ -0,0 +1,5 @@
+contract interface I =
+    entrypoint f : () => int
+
+contract C : I =
+    stateful entrypoint f() = 1

test/contracts/polymorphism_change_entrypoint_to_function.aes

@@ -0,0 +1,6 @@
+contract interface I =
+    entrypoint f : () => int
+
+contract C : I =
+    entrypoint init() = ()
+    function f() = 1

test/contracts/polymorphism_non_payable_contract_implement_payable.aes

@@ -0,0 +1,5 @@
+payable contract interface I =
+    payable entrypoint f : () => int
+
+contract C : I =
+    entrypoint f() = 123

test/contracts/polymorphism_non_payable_interface_implement_payable.aes

@@ -0,0 +1,8 @@
+payable contract interface I =
+    payable entrypoint f : () => int
+
+contract interface H : I =
+    payable entrypoint f : () => int
+
+payable contract C : H =
+    entrypoint f() = 123

test/contracts/polymorphism_preserve_or_add_payable_contract.aes

@@ -0,0 +1,14 @@
+contract interface F =
+    entrypoint f : () => int
+
+payable contract interface G : F =
+    payable entrypoint f : () => int
+    entrypoint g : () => int
+
+payable contract interface H =
+    payable entrypoint h : () => int
+
+payable contract C : G, H =
+    payable entrypoint f() = 1
+    payable entrypoint g() = 2
+    payable entrypoint h() = 3

test/contracts/polymorphism_preserve_or_add_payable_entrypoint.aes

@@ -0,0 +1,7 @@
+contract interface I =
+    payable entrypoint f : () => int
+    entrypoint g : () => int
+
+contract C : I =
+    payable entrypoint f() = 1
+    payable entrypoint g() = 2

test/contracts/polymorphism_preserve_or_remove_stateful_entrypoint.aes

@@ -0,0 +1,7 @@
+contract interface I =
+    stateful entrypoint f : () => int
+    stateful entrypoint g : () => int
+
+contract C : I =
+    stateful entrypoint f() = 1
+    entrypoint g() = 2

test/contracts/polymorphism_remove_payable_entrypoint.aes

@@ -0,0 +1,5 @@
+contract interface I =
+    payable entrypoint f : () => int
+
+contract C : I =
+    entrypoint f() = 1

test/contracts/polymorphism_variance_switching_chain_create.aes

@@ -0,0 +1,29 @@
+contract interface I =
+    entrypoint f : () => int
+
+contract C1 : I =
+    entrypoint f() = 123
+
+contract C2 : I =
+    entrypoint f() = 888
+
+namespace Make =
+    stateful function new1() : I = Chain.create() : C1
+    stateful function new2() : I = Chain.create() : C2
+
+    stateful function new(c : I) : int = c.f()
+
+main contract Main =
+    stateful entrypoint test1() =
+        let c = Make.new1()
+        Make.new(c)
+
+    stateful entrypoint test2() =
+        let c = Make.new2()
+        Make.new(c)
+
+    stateful entrypoint test3() =
+        let c1      = Chain.create() : C1  // succeeds
+        let c2 : I  = Chain.create() : C1  // succeeds
+        let c3 : C1 = Chain.create()       // succeeds
+        ()

test/contracts/polymorphism_variance_switching_chain_create_fail.aes

@@ -0,0 +1,12 @@
+contract interface I =
+    entrypoint f : () => int
+
+contract C : I =
+    entrypoint f() = 123
+
+main contract Main =
+    stateful entrypoint test() =
+        let c1 : I = Chain.create()       // fails
+        let c2 : C = Chain.create() : I   // fails
+        let c3     = Chain.create() : I   // fails
+        ()

test/contracts/polymorphism_variance_switching_unify_with_interface_decls.aes

@@ -0,0 +1,5 @@
+payable contract interface SalesOffer =
+    entrypoint init : (address, address, int, int) => unit
+
+payable contract Test : SalesOffer =
+    entrypoint init(_, _, _, _) = ()

test/contracts/polymorphism_variance_switching_void_supertype.aes

@@ -0,0 +1,5 @@
+payable contract interface SalesOffer =
+    entrypoint init : (address, address, int, int) => void
+
+payable contract Test : SalesOffer =
+    entrypoint init(_ : address, _ : address, _ : int, _ : int) = ()

test/contracts/resolve_field_constraint_by_arity.aes

@@ -0,0 +1,9 @@
+contract First =
+    entrypoint print_num(x) = 1 + x
+
+contract Second =
+    entrypoint print_num() = 1
+
+main contract Test =
+    entrypoint f(c) = c.print_num(1)
+    entrypoint g(c) = c.print_num()

test/contracts/spend_test.aes

@@ -1,7 +1,4 @@
 
-contract interface SpendContract =
-  entrypoint withdraw : (int) => int
-
 contract SpendTest =
 
   stateful entrypoint spend(to, amount) =

test/contracts/using_contract_as_namespace.aes

@@ -0,0 +1,7 @@
+contract F =
+  entrypoint g() = 1
+
+main contract C =
+  using F for [g]
+
+  entrypoint f() = g()

test/contracts/var_args_unify_fun_call.aes

@@ -0,0 +1,7 @@
+contract C =
+  stateful function g(h) =
+    h()
+
+  stateful entrypoint f() =
+    g(Chain.create)
+    123

test/contracts/var_args_unify_let.aes

@@ -0,0 +1,4 @@
+main contract C =
+  stateful entrypoint f() =
+    let x = Chain.clone
+    123

test/contracts/warnings.aes

@@ -12,7 +12,7 @@ namespace UnusedNamespace =
   // Unused
   private function h() = 3
 
-contract Warnings =
+main contract Warnings =
 
   type state = int
 
@@ -58,3 +58,10 @@ namespace FunctionsAsArgs =
     private function inc(n : int) : int = n + 1
     // Never used
     private function dec(n : int) : int = n - 1
+
+contract Remote =
+  entrypoint id(_) = 0
+
+contract C = 
+  payable stateful entrypoint
+    call_missing_con() : int = (ct_1111111111111111111111111111112JF6Dz72 : Remote).id(value = 1, 0)