diff --git a/CHANGELOG.md b/CHANGELOG.md
index 02e3a35..e693f8d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 ### Added
+- Added the `[a..b]` language construct, returning the list of numbers between
+  `a` and `b` (inclusive). Returns the empty list if `a` > `b`.
 ### Changed
 ### Removed
 
diff --git a/priv/stdlib/Func.aes b/priv/stdlib/Func.aes
new file mode 100644
index 0000000..7d633a2
--- /dev/null
+++ b/priv/stdlib/Func.aes
@@ -0,0 +1,46 @@
+namespace Func =
+
+  function id(x : 'a) : 'a = x
+
+  function const(x : 'a) : 'b => 'a = (y) => x
+
+  function flip(f : ('a, 'b) => 'c) : ('b, 'a) => 'c = (b, a) => f(a, b)
+
+  function comp(f : 'b => 'c, g : 'a => 'b) : 'a => 'c = (x) => f(g(x))
+
+  function pipe(f : 'a => 'b, g : 'b => 'c) : 'a => 'c = (x) => g(f(x))
+
+  function rapply(x : 'a, f : 'a => 'b) : 'b = f(x)
+
+  /* The Z combinator - replacement for local and anonymous recursion.
+   */
+  function recur(f : ('arg => 'res, 'arg) => 'res) : 'arg => 'res =
+    (x) => f(recur(f), x)
+
+  function iter(n : int, f : 'a => 'a) : 'a => 'a = iter_(n, f, (x) => x)
+  private function iter_(n : int, f : 'a => 'a, acc : 'a => 'a) : 'a => 'a =
+    if(n == 0) acc
+    elif(n == 1) comp(f, acc)
+    else iter_(n / 2, comp(f, f), if(n mod 2 == 0) acc else comp(f, acc))
+
+  function curry2(f : ('a, 'b) => 'c) : 'a => ('b => 'c) =
+    (x) => (y) => f(x, y)
+  function curry3(f : ('a, 'b, 'c) => 'd) : 'a => ('b => ('c => 'd)) =
+    (x) => (y) => (z) => f(x, y, z)
+
+  function uncurry2(f : 'a => ('b => 'c)) : ('a, 'b) => 'c =
+    (x, y) => f(x)(y)
+  function uncurry3(f : 'a => ('b => ('c => 'd))) : ('a, 'b, 'c) => 'd =
+    (x, y, z) => f(x)(y)(z)
+
+  function tuplify2(f : ('a, 'b) => 'c) : (('a * 'b)) => 'c =
+    (t) => switch(t)
+      (x, y) => f(x, y)
+  function tuplify3(f : ('a, 'b, 'c) => 'd) : 'a * 'b * 'c => 'd =
+    (t) => switch(t)
+      (x, y, z) => f(x, y, z)
+
+  function untuplify2(f : 'a * 'b => 'c) : ('a, 'b) => 'c =
+    (x, y) => f((x, y))
+  function untuplify3(f : 'a * 'b * 'c => 'd) : ('a, 'b, 'c) => 'd =
+    (x, y, z) => f((x, y, z))
diff --git a/priv/stdlib/List.aes b/priv/stdlib/List.aes
new file mode 100644
index 0000000..cdd2464
--- /dev/null
+++ b/priv/stdlib/List.aes
@@ -0,0 +1,207 @@
+include "ListInternal.aes"
+
+namespace List =
+
+  function is_empty(l : list('a)) : bool = switch(l)
+    [] => true
+    _  => false
+
+  function first(l : list('a)) : option('a) = switch(l)
+    []   => None
+    h::_ => Some(h)
+
+  function tail(l : list('a)) : option(list('a)) = switch(l)
+    []   => None
+    _::t => Some(t)
+
+  function last(l : list('a)) : option('a) = switch(l)
+    []  => None
+    [x] => Some(x)
+    _::t => last(t)
+
+  function find(p : 'a => bool, l : list('a)) : option('a) = switch(l)
+    []   => None
+    h::t => if(p(h)) Some(h) else find(p, t)
+
+  function find_all(p : 'a => bool, l : list('a)) : list('a) = find_all_(p, l, [])
+  private function find_all_(p : 'a => bool, l : list('a), acc : list('a)) : list('a) = switch(l)
+    []   => reverse(acc)
+    h::t => find_all_(p, t, if(p(h)) h::acc else acc)
+
+  function find_indices(p : 'a => bool, l : list('a)) : list(int) = find_indices_(p, l, 0, [])
+  private function find_indices_( p : 'a => bool
+                                , l : list('a)
+                                , n : int
+                                , acc : list(int)
+                                ) : list(int) = switch(l)
+    []   => reverse(acc)
+    h::t => find_indices_(p, t, n+1, if(p(h)) n::acc else acc)
+
+  function nth(n : int, l : list('a)) : option('a) = switch(l)
+    []   => None
+    h::t => if(n == 0) Some(h) else nth(n-1, t)
+
+  /* Unsafe version of `nth` */
+  function get(n : int, l : list('a)) : 'a = switch(l)
+    [] => abort("Out of index get")
+    h::t => if(n == 0) h else get(n-1, t)
+
+
+  function length(l : list('a)) : int = length_(l, 0)
+  private function length_(l : list('a), acc : int) : int = switch(l)
+    []   => acc
+    _::t => length_(t, acc + 1)
+
+
+  /* Unsafe. Replaces `n`th element of `l` with `e`. Crashes on over/underflow */
+  function replace_at(n : int, e : 'a, l : list('a)) : list('a) =
+    if(n<0) abort("insert_at underflow") else replace_at_(n, e, l, [])
+  private function replace_at_(n : int, e : 'a, l : list('a), acc : list('a)) : list('a) =
+   switch(l)
+     []   => abort("replace_at overflow")
+     h::t => if (n == 0) reverse(e::acc) ++ t
+             else replace_at_(n-1, e, t, h::acc)
+
+  /* Unsafe. Adds `e` to `l` to be its `n`th element. Crashes on over/underflow */
+  function insert_at(n : int, e : 'a, l : list('a)) : list('a) =
+    if(n<0) abort("insert_at underflow") else insert_at_(n, e, l, [])
+  private function insert_at_(n : int, e : 'a, l : list('a), acc : list('a)) : list('a) =
+   if (n == 0) reverse(e::acc) ++ l
+   else switch(l)
+     []   => abort("insert_at overflow")
+     h::t => insert_at_(n-1, e, t, h::acc)
+
+  function insert_by(f : (('a, 'a) => bool), x : 'a, l : list('a)) : list('a) =
+    switch(l)
+      []        => [x]
+      (e :: l') =>
+        if(f(x, e))
+          e :: insert_by(f, x, l')
+        else
+          x :: l
+
+  function foldr(cons : ('a, 'b) => 'b, nil : 'b, l : list('a)) : 'b = switch(l)
+    []   => nil
+    h::t => cons(h, foldr(cons, nil, t))
+
+  function foldl(rcons : ('b, 'a) => 'b, acc : 'b, l : list('a)) : 'b = switch(l)
+    []   => acc
+    h::t => foldl(rcons, rcons(acc, h), t)
+
+  function foreach(f : 'a => unit, l : list('a)) : unit =
+    switch(l)
+     []   => ()
+     e :: l' =>
+       f(e)
+       foreach(f, l')
+
+  function reverse(l : list('a)) : list('a) = foldl((lst, el) => el :: lst, [], l)
+
+  function map(f : 'a => 'b, l : list('a)) : list('b) = map_(f, l, [])
+  private function map_(f : 'a => 'b, l : list('a), acc : list('b)) : list('b) = switch(l)
+    []   => reverse(acc)
+    h::t => map_(f, t, f(h)::acc)
+
+  function flat_map(f : 'a => list('b), l : list('a)) : list('b) =
+    ListInternal.flat_map(f, l)
+
+  function filter(p : 'a => bool, l : list('a)) : list('a) = filter_(p, l, [])
+  private function filter_(p : 'a => bool, l : list('a), acc : list('a)) : list('a) = switch(l)
+    []   => reverse(acc)
+    h::t => filter_(p, t, if(p(h)) h::acc else acc)
+
+  /* Take `n` first elements */
+  function take(n : int, l : list('a)) : list('a) =
+    if(n < 0) abort("Take negative number of elements") else take_(n, l, [])
+  private function take_(n : int, l : list('a), acc : list('a)) : list('a) =
+    if(n == 0) reverse(acc)
+    else switch(l)
+      []   => reverse(acc)
+      h::t => take_(n-1, t, h::acc)
+
+  /* Drop `n` first elements */
+  function drop(n : int, l : list('a)) : list('a) =
+   if(n < 0) abort("Drop negative number of elements")
+   elif (n == 0) l
+   else switch(l)
+      []   => []
+      h::t => drop(n-1, t)
+
+  /* Get the longest prefix of a list in which every element matches predicate `p` */
+  function take_while(p : 'a => bool, l : list('a)) : list('a) = take_while_(p, l, [])
+  private function take_while_(p : 'a => bool, l : list('a), acc : list('a)) : list('a) = switch(l)
+    []   => reverse(acc)
+    h::t => if(p(h)) take_while_(p, t, h::acc) else reverse(acc)
+
+  /* Drop elements from `l` until `p` holds */
+  function drop_while(p : 'a => bool, l : list('a)) : list('a) = switch(l)
+    []   => []
+    h::t => if(p(h)) drop_while(p, t) else l
+
+  /* Splits list into two lists of elements that respectively match and don't match predicate `p` */
+  function partition(p : 'a => bool, l : list('a)) : (list('a) * list('a)) = partition_(p, l, [], [])
+  private function partition_( p : 'a => bool
+                             , l : list('a)
+                             , acc_t : list('a)
+                             , acc_f : list('a)
+                             ) : (list('a) * list('a)) = switch(l)
+    []   => (reverse(acc_t), reverse(acc_f))
+    h::t => if(p(h)) partition_(p, t, h::acc_t, acc_f) else partition_(p, t, acc_t, h::acc_f)
+
+
+  function concats(ll : list(list('a))) : list('a) = foldr((l1, l2) => l1 ++ l2, [], ll)
+
+  function all(p : 'a => bool, l : list('a)) : bool = switch(l)
+    []   => true
+    h::t => if(p(h)) all(p, t) else false
+
+  function any(p : 'a => bool, l : list('a)) : bool = switch(l)
+    []   => false
+    h::t => if(p(h)) true else any(p, t)
+
+  function sum(l : list(int)) : int = foldl ((a, b) => a + b, 0, l)
+
+  function product(l : list(int)) : int = foldl((a, b) => a * b, 1, l)
+
+
+  /* Zips two list by applying bimapping function on respective elements. Drops longer tail. */
+  function zip_with(f : ('a, 'b) => 'c, l1 : list('a), l2 : list('b)) : list('c) = zip_with_(f, l1, l2, [])
+  private function zip_with_( f : ('a, 'b) => 'c
+                            , l1 : list('a)
+                            , l2 : list('b)
+                            , acc : list('c)
+                            ) : list('c) = switch ((l1, l2))
+    (h1::t1, h2::t2) => zip_with_(f, t1, t2, f(h1, h2)::acc)
+    _ => reverse(acc)
+
+  /* Zips two lists into list of pairs. Drops longer tail. */
+  function zip(l1 : list('a), l2 : list('b)) : list('a * 'b) = zip_with((a, b) => (a, b), l1, l2)
+
+  function unzip(l : list('a * 'b)) : list('a) * list('b) = unzip_(l, [], [])
+  private function unzip_( l     : list('a * 'b)
+                         , acc_l : list('a)
+                         , acc_r : list('b)
+                         ) : (list('a) * list('b)) = switch(l)
+    []               => (reverse(acc_l), reverse(acc_r))
+    (left, right)::t => unzip_(t, left::acc_l, right::acc_r)
+
+
+  // TODO: Improve?
+  function sort(lesser_cmp : ('a, 'a) => bool, l : list('a)) : list('a) = switch(l)
+    []   => []
+    h::t => switch (partition((x) => lesser_cmp(x, h), t))
+      (lesser, bigger) => sort(lesser_cmp, lesser) ++ h::sort(lesser_cmp, bigger)
+
+
+  function intersperse(delim : 'a, l : list('a)) : list('a) = intersperse_(delim, l, [])
+  private function intersperse_(delim : 'a, l : list('a), acc : list('a)) : list('a) = switch(l)
+    []   => reverse(acc)
+    [e]  => reverse(e::acc)
+    h::t => intersperse_(delim, t, delim::h::acc)
+
+
+  function enumerate(l : list('a)) : list(int * 'a) = enumerate_(l, 0, [])
+  private function enumerate_(l : list('a), n : int, acc : list(int * 'a)) : list(int * 'a) = switch(l)
+    []   => reverse(acc)
+    h::t => enumerate_(t, n + 1, (n, h)::acc)
+
diff --git a/priv/stdlib/ListInternal.aes b/priv/stdlib/ListInternal.aes
new file mode 100644
index 0000000..7d6773a
--- /dev/null
+++ b/priv/stdlib/ListInternal.aes
@@ -0,0 +1,16 @@
+namespace ListInternal =
+
+  // -- Flatmap ----------------------------------------------------------------
+
+  function flat_map(f : 'a => list('b), xs : list('a)) : list('b) =
+    switch(xs)
+      []      => []
+      x :: xs => f(x) ++ flat_map(f, xs)
+
+  // -- From..to ---------------------------------------------------------------
+
+  function from_to(a : int, b : int) : list(int) = from_to_(a, b, [])
+
+  private function from_to_(a, b, acc) =
+    if (a > b) acc else from_to_(a, b - 1, b :: acc)
+
diff --git a/priv/stdlib/Option.aes b/priv/stdlib/Option.aes
new file mode 100644
index 0000000..843e62d
--- /dev/null
+++ b/priv/stdlib/Option.aes
@@ -0,0 +1,76 @@
+include "List.aes"
+
+namespace Option =
+
+  function is_none(o : option('a)) : bool = switch(o)
+    None => true
+    Some(_) => false
+
+  function is_some(o : option('a)) : bool = switch(o)
+    None => false
+    Some(_) => true
+
+
+  function match(n : 'b, s : 'a => 'b, o : option('a)) : 'b = switch(o)
+    None => n
+    Some(x) => s(x)
+
+  function default(def : 'a, o : option('a)) : 'a = match(def, (x) => x, o)
+
+  function force(o : option('a)) : 'a = default(abort("Forced None value"), o)
+
+  function on_elem(f : 'a => unit, o : option('a)) : unit = match((), f, o)
+
+  function map(f : 'a => 'b, o : option('a)) : option('b) = switch(o)
+    None => None
+    Some(x) => Some(f(x))
+
+  function map2(f : ('a, 'b) => 'c
+               , o1 : option('a)
+               , o2 : option('b)
+               ) : option('c) = switch((o1, o2))
+    (Some(x1), Some(x2)) => Some(f(x1, x2))
+    _ => None
+
+  function map3( f : ('a, 'b, 'c) => 'd
+               , o1 : option('a)
+               , o2 : option('b)
+               , o3 : option('c)
+               ) : option('d) = switch((o1, o2, o3))
+    (Some(x1), Some(x2), Some(x3)) => Some(f(x1, x2, x3))
+    _ => None
+
+  function app_over(f : option ('a => 'b), o : option('a)) : option('b) = switch((f, o))
+    (Some(ff), Some(xx)) => Some(ff(xx))
+    _ => None
+
+  function flat_map(f : 'a => option('b), o : option('a)) : option('b) = switch(o)
+    None => None
+    Some(x) => f(x)
+
+
+  function to_list(o : option('a)) : list('a) = switch(o)
+    None => []
+    Some(x) => [x]
+
+  function filter_options(l : list(option('a))) : list('a) = filter_options_(l, [])
+  private function filter_options_(l : list (option('a)), acc : list('a)) : list('a) = switch(l)
+    []         => List.reverse(acc)
+    None::t    => filter_options_(t, acc)
+    Some(x)::t => filter_options_(t, x::acc)
+
+  function seq_options(l : list (option('a))) : option (list('a)) = seq_options_(l, [])
+  private function seq_options_(l : list (option('a)), acc : list('a)) : option(list('a)) = switch(l)
+    []         => Some(List.reverse(acc))
+    None::t    => None
+    Some(x)::t => seq_options_(t, x::acc)
+
+
+  function choose(o1 : option('a), o2 : option('a)) : option('a) =
+    if(is_some(o1)) o1 else o2
+
+  function choose_first(l : list(option('a))) : option('a) = switch(l)
+    [] => None
+    None::t    => choose_first(t)
+    Some(x)::_ => Some(x)
+
diff --git a/priv/stdlib/Pair.aes b/priv/stdlib/Pair.aes
new file mode 100644
index 0000000..22312e3
--- /dev/null
+++ b/priv/stdlib/Pair.aes
@@ -0,0 +1,20 @@
+namespace Pair =
+
+  function fst(t : ('a * 'b)) : 'a = switch(t)
+    (x, _) => x
+
+  function snd(t : ('a * 'b)) : 'b = switch(t)
+    (_, y) => y
+
+  function map1(f : 'a => 'c, t : ('a * 'b)) : ('c * 'b) = switch(t)
+    (x, y) => (f(x), y)
+
+  function map2(f : 'b => 'c, t : ('a * 'b)) : ('a * 'c) = switch(t)
+    (x, y) => (x, f(y))
+
+  function bimap(f : 'a => 'c, g : 'b => 'd, t : ('a * 'b)) : ('c * 'd) = switch(t)
+    (x, y) => (f(x), g(y))
+
+  function swap(t : ('a * 'b)) : ('b * 'a) = switch(t)
+    (x, y) => (y, x)
+
diff --git a/priv/stdlib/Triple.aes b/priv/stdlib/Triple.aes
new file mode 100644
index 0000000..84f3ddd
--- /dev/null
+++ b/priv/stdlib/Triple.aes
@@ -0,0 +1,37 @@
+namespace Triple =
+
+  function fst(t : ('a * 'b * 'c)) : 'a = switch(t)
+    (x, _, _) => x
+
+  function snd(t : ('a * 'b * 'c)) : 'b = switch(t)
+    (_, y, _) => y
+
+  function thd(t : ('a * 'b * 'c)) : 'c = switch(t)
+    (_, _, z) => z
+
+
+  function map1(f : 'a => 'm, t : ('a * 'b * 'c)) : ('m * 'b * 'c) = switch(t)
+    (x, y, z) => (f(x), y, z)
+
+  function map2(f : 'b => 'm, t : ('a * 'b * 'c)) : ('a * 'm * 'c) = switch(t)
+    (x, y, z) => (x, f(y), z)
+
+  function map3(f : 'c => 'm, t : ('a * 'b * 'c)) : ('a * 'b * 'm) = switch(t)
+    (x, y, z) => (x, y, f(z))
+
+  function trimap( f : 'a => 'x
+                 , g : 'b => 'y
+                 , h : 'c => 'z
+                 , t : ('a * 'b * 'c)
+                 ) : ('x * 'y * 'z) = switch(t)
+    (x, y, z) => (f(x), g(y), h(z))
+
+  function swap(t : ('a * 'b * 'c)) : ('c * 'b * 'a) = switch(t)
+    (x, y, z) => (z, y, x)
+
+  function rotr(t : ('a * 'b * 'c)) : ('c * 'a * 'b) = switch(t)
+    (x, y, z) => (z, x, y)
+
+  function rotl(t : ('a * 'b * 'c)) : ('b * 'c * 'a) = switch(t)
+    (x, y, z) => (y, z, x)
+
diff --git a/src/aeso_ast_infer_types.erl b/src/aeso_ast_infer_types.erl
index 6993768..5a07a9f 100644
--- a/src/aeso_ast_infer_types.erl
+++ b/src/aeso_ast_infer_types.erl
@@ -767,7 +767,9 @@ check_type(Env, Type = {fun_t, Ann, NamedArgs, Args, Ret}, Arity) ->
     {fun_t, Ann, NamedArgs1, Args1, Ret1};
 check_type(_Env, Type = {uvar, _, _}, Arity) ->
     ensure_base_type(Type, Arity),
-    Type.
+    Type;
+check_type(_Env, {args_t, Ann, Ts}, _) ->
+    type_error({new_tuple_syntax, Ann, Ts}).
 
 ensure_base_type(Type, Arity) ->
     [ type_error({wrong_type_arguments, Type, Arity, 0}) || Arity /= 0 ],
@@ -1352,6 +1354,9 @@ infer_infix({RelOp, As})
     T = fresh_uvar(As),     %% allow any type here, check in ast_to_icode that we have comparison for it
     Bool = {id, As, "bool"},
     {fun_t, As, [], [T, T], Bool};
+infer_infix({'..', As}) ->
+    Int = {id, As, "int"},
+    {fun_t, As, [], [Int, Int], {app_t, As, {id, As, "list"}, [Int]}};
 infer_infix({'::', As}) ->
     ElemType = fresh_uvar(As),
     ListType = {app_t, As, {id, As, "list"}, [ElemType]},
@@ -2219,6 +2224,9 @@ pp_error({contract_has_no_entrypoints, Con}) ->
                   "'function'.\n", [pp_expr("", Con), pp_loc(Con)]);
 pp_error({unbound_type, Type}) ->
     io_lib:format("Unbound type ~s (at ~s).\n", [pp_type("", Type), pp_loc(Type)]);
+pp_error({new_tuple_syntax, Ann, Ts}) ->
+    io_lib:format("Invalid type\n~s  (at ~s)\nThe syntax of tuple types changed in Sophia version 4.0. Did you mean\n~s\n",
+                  [pp_type("  ", {args_t, Ann, Ts}), pp_loc(Ann), pp_type("  ", {tuple_t, Ann, Ts})]);
 pp_error(Err) ->
     io_lib:format("Unknown error: ~p\n", [Err]).
 
diff --git a/src/aeso_ast_to_fcode.erl b/src/aeso_ast_to_fcode.erl
index 0b83908..16fe99e 100644
--- a/src/aeso_ast_to_fcode.erl
+++ b/src/aeso_ast_to_fcode.erl
@@ -453,12 +453,16 @@ 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]}) ->
+    {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, {typed, {id, _, Arg}, _}, BindExpr}|Rest]}) ->
     Env1 = bind_var(Env, Arg),
     Bind = {lam, [Arg], expr_to_fcode(Env1, {list_comp, As, Yield, Rest})},
-    {def_u, FlatMap, _} = resolve_fun(Env, ["List", "flat_map"]),
+    {def_u, FlatMap, _} = resolve_fun(Env, ["ListInternal", "flat_map"]),
     {def, FlatMap, [Bind, expr_to_fcode(Env, BindExpr)]};
 expr_to_fcode(Env, Type, {list_comp, As, Yield, [{comprehension_if, _, Cond}|Rest]}) ->
     make_if(expr_to_fcode(Env, Cond),
diff --git a/src/aeso_ast_to_icode.erl b/src/aeso_ast_to_icode.erl
index 7b0c839..ca1433a 100644
--- a/src/aeso_ast_to_icode.erl
+++ b/src/aeso_ast_to_icode.erl
@@ -523,6 +523,10 @@ ast_body({app, _, {typed, _, {con, _, Name}, _}, Args}, Icode) ->
 ast_body({app, _, {typed, _, {qcon, _, Name}, _}, Args}, Icode) ->
     Tag = aeso_icode:get_constructor_tag(Name, Icode),
     #tuple{cpts = [#integer{value = Tag} | [ ast_body(Arg, Icode) || Arg <- Args ]]};
+ast_body({app, _, {'..', _}, [A, B]}, Icode) ->
+    #funcall
+    { function = #var_ref{ name = ["ListInternal", "from_to"] }
+    , args     = [ast_body(A, Icode), ast_body(B, Icode)] };
 ast_body({app,As,Fun,Args}, Icode) ->
     case aeso_syntax:get_ann(format, As) of
         infix  ->
@@ -541,7 +545,7 @@ ast_body({list_comp, _, Yield, []}, Icode) ->
     #list{elems = [ast_body(Yield, Icode)]};
 ast_body({list_comp, As, Yield, [{comprehension_bind, {typed, Arg, ArgType}, BindExpr}|Rest]}, Icode) ->
     #funcall
-        { function = #var_ref{ name = ["List", "flat_map"] }
+        { function = #var_ref{ name = ["ListInternal", "flat_map"] }
         , args =
               [ #lambda{ args=[#arg{name = ast_id(Arg), type = ast_type(ArgType, Icode)}]
                        , body = ast_body({list_comp, As, Yield, Rest}, Icode)
diff --git a/src/aeso_compiler.erl b/src/aeso_compiler.erl
index dadfbc8..eeba90c 100644
--- a/src/aeso_compiler.erl
+++ b/src/aeso_compiler.erl
@@ -36,7 +36,6 @@
                 | pp_assembler
                 | pp_bytecode
                 | no_code
-                | no_implicit_stdlib
                 | {backend, aevm | fate}
                 | {include, {file_system, [string()]} |
                             {explicit_files, #{string() => binary()}}}
@@ -142,16 +141,7 @@ from_string1(fate, ContractString, Options) ->
 
 -spec string_to_code(string(), options()) -> map().
 string_to_code(ContractString, Options) ->
-    Ast = case lists:member(no_implicit_stdlib, Options) of
-              true -> parse(ContractString, Options);
-              false ->
-                  IncludedSTD = sets:from_list(
-                                  [aeso_parser:hash_include(F, C)
-                                   || {F, C} <- aeso_stdlib:stdlib_list()]),
-                  InitAst = parse(ContractString, IncludedSTD, Options),
-                  STD = parse_stdlib(),
-                  STD ++ InitAst
-          end,
+    Ast = parse(ContractString, Options),
     pp_sophia_code(Ast, Options),
     pp_ast(Ast, Options),
     {TypeEnv, TypedAst} = aeso_ast_infer_types:infer(Ast, [return_env]),
@@ -317,7 +307,7 @@ to_sophia_value(_, _, revert, Data, Options) ->
             {ok, {app, [], {id, [], "abort"}, [{string, [], Err}]}}
     end;
 to_sophia_value(ContractString, FunName, ok, Data, Options0) ->
-    Options = [no_implicit_stdlib, no_code | Options0],
+    Options = [no_code | Options0],
     try
         Code = string_to_code(ContractString, Options),
         #{ typed_ast := TypedAst, type_env  := TypeEnv} = Code,
@@ -378,7 +368,7 @@ create_calldata(Code, Fun, Args) ->
                              {ok, binary()}
                              | {error, term()}.
 create_calldata(Code, Fun, Args, Options0) ->
-    Options = [no_implicit_stdlib, no_code | Options0],
+    Options = [no_code | Options0],
     case proplists:get_value(backend, Options, aevm) of
         aevm ->
             case check_call(Code, Fun, Args, Options) of
@@ -401,7 +391,7 @@ decode_calldata(ContractString, FunName, Calldata) ->
     decode_calldata(ContractString, FunName, Calldata, [{backend, aevm}]).
 
 decode_calldata(ContractString, FunName, Calldata, Options0) ->
-    Options = [no_implicit_stdlib, no_code | Options0],
+    Options = [no_code | Options0],
     try
         Code = string_to_code(ContractString, Options),
         #{ typed_ast := TypedAst, type_env  := TypeEnv} = Code,
@@ -579,15 +569,6 @@ pp(Code, Options, Option, PPFun) ->
 
 %% -------------------------------------------------------------------
 
--spec parse_stdlib() -> none() | aeso_syntax:ast().
-parse_stdlib() ->
-    lists:foldr(
-      fun ({Lib, LibCode}, Acc) ->
-              parse(LibCode, [{src_file, binary_to_list(Lib)}]) ++ Acc
-      end,
-      [],
-      aeso_stdlib:stdlib_list()).
-
 sophia_type_to_typerep(String) ->
     {ok, Ast} = aeso_parser:type(String),
     try aeso_ast_to_icode:ast_typerep(Ast) of
diff --git a/src/aeso_parser.erl b/src/aeso_parser.erl
index c53712e..38e6d64 100644
--- a/src/aeso_parser.erl
+++ b/src/aeso_parser.erl
@@ -150,7 +150,7 @@ type() -> ?LAZY_P(type100()).
 type100() -> type200().
 
 type200() ->
-    ?RULE(many({fun_domain(), keyword('=>')}), type300(), fun_t(_1, _2)).
+    ?RULE(many({type300(), keyword('=>')}), type300(), fun_t(_1, _2)).
 
 type300() ->
     ?RULE(sep1(type400(), tok('*')), tuple_t(get_ann(lists:nth(1, _1)), _1)).
@@ -169,16 +169,15 @@ type400() ->
 typeAtom() ->
     ?LAZY_P(choice(
     [ parens(type())
+    , args_t()
     , id(), token(con), token(qcon), token(qid), tvar()
     ])).
 
-fun_domain() -> ?LAZY_P(choice(
-    [ ?RULE(tok('('), tok(')'), [])
-      %% Note avoidance of ambiguity: `(int)` can be treated as:
-      %% - literally `int`
-      %% - list of arguments with just one element – int. This approach is dropped.
-    , ?RULE(tok('('), type(), tok(','), sep1(type(), tok(',')), tok(')'), [_2|_4])
-    , ?RULE(type300(), [_1])
+args_t() ->
+    ?LAZY_P(choice(
+    [ ?RULE(tok('('), tok(')'), {args_t, get_ann(_1), []})
+      %% Singleton case handled separately
+    , ?RULE(tok('('), type(), tok(','), sep1(type(), tok(',')), tok(')'), {args_t, get_ann(_1), [_2|_4]})
     ])).
 
 %% -- Statements -------------------------------------------------------------
@@ -501,7 +500,8 @@ tuple_t(_Ann, [Type]) -> Type;  %% Not a tuple
 tuple_t(Ann, Types)   -> {tuple_t, Ann, Types}.
 
 fun_t(Domains, Type) ->
-    lists:foldr(fun({Dom, Ann}, T) -> {fun_t, Ann, [], Dom, T} end,
+    lists:foldr(fun({{args_t, _, Dom}, Ann}, T) -> {fun_t, Ann, [], Dom, T};
+                    ({Dom, Ann}, T)             -> {fun_t, Ann, [], [Dom], T} end,
                 Type, Domains).
 
 tuple_e(_Ann, [Expr]) -> Expr;  %% Not a tuple
@@ -549,12 +549,16 @@ bad_expr_err(Reason, E) ->
                             prettypr:nest(2, aeso_pretty:expr(E))])).
 
 %% -- Helper functions -------------------------------------------------------
+
 expand_includes(AST, Included, Opts) ->
-    expand_includes(AST, Included, [], Opts).
+    Ann  = [{origin, system}],
+    AST1 = [ {include, Ann, {string, Ann, File}}
+             || File <- lists:usort(auto_imports(AST)) ] ++ AST,
+    expand_includes(AST1, Included, [], Opts).
 
 expand_includes([], _Included, Acc, _Opts) ->
     {ok, lists:reverse(Acc)};
-expand_includes([{include, Ann, {string, SAnn, File}} | AST], Included, Acc, Opts) ->
+expand_includes([{include, Ann, {string, _SAnn, File}} | AST], Included, Acc, Opts) ->
     case get_include_code(File, Ann, Opts) of
         {ok, Code} ->
             Hashed = hash_include(File, Code),
@@ -562,12 +566,9 @@ expand_includes([{include, Ann, {string, SAnn, File}} | AST], Included, Acc, Opt
                 false ->
                     Opts1 = lists:keystore(src_file, 1, Opts, {src_file, File}),
                     Included1 = sets:add_element(Hashed, Included),
-                    case string(Code, Included1, Opts1) of
+                    case parse_and_scan(file(), Code, Opts1) of
                         {ok, AST1} ->
-                            Dependencies = [ {include, Ann, {string, SAnn, Dep}}
-                                             || Dep <- aeso_stdlib:dependencies(File)
-                                           ],
-                            expand_includes(Dependencies ++ AST1 ++ AST, Included1, Acc, Opts);
+                            expand_includes(AST1 ++ AST, Included1, Acc, Opts);
                         Err = {error, _} ->
                             Err
                     end;
@@ -593,12 +594,15 @@ read_file(File, Opts) ->
             end
     end.
 
+stdlib_options() ->
+    [{include, {file_system, [aeso_stdlib:stdlib_include_path()]}}].
+
 get_include_code(File, Ann, Opts) ->
-    case {read_file(File, Opts), maps:find(File, aeso_stdlib:stdlib())} of
+    case {read_file(File, Opts), read_file(File, stdlib_options())} of
         {{ok, _}, {ok,_ }} ->
             return_error(ann_pos(Ann), "Illegal redefinition of standard library " ++ File);
-        {_, {ok, Lib}} ->
-            {ok, Lib};
+        {_, {ok, Bin}} ->
+            {ok, binary_to_list(Bin)};
         {{ok, Bin}, _} ->
             {ok, binary_to_list(Bin)};
         {_, _} ->
@@ -610,3 +614,11 @@ hash_include(File, Code) when is_binary(File) ->
     hash_include(binary_to_list(File), Code);
 hash_include(File, Code) when is_list(File) ->
     {filename:basename(File), crypto:hash(sha256, Code)}.
+
+auto_imports({comprehension_bind, _, _}) -> [<<"ListInternal.aes">>];
+auto_imports({'..', _})                  -> [<<"ListInternal.aes">>];
+auto_imports(L) when is_list(L) ->
+    lists:flatmap(fun auto_imports/1, L);
+auto_imports(T) when is_tuple(T) ->
+    auto_imports(tuple_to_list(T));
+auto_imports(_) -> [].
diff --git a/src/aeso_pretty.erl b/src/aeso_pretty.erl
index e368354..dc36374 100644
--- a/src/aeso_pretty.erl
+++ b/src/aeso_pretty.erl
@@ -243,6 +243,8 @@ type({app_t, _, Type, Args}) ->
     beside(type(Type), args_type(Args));
 type({tuple_t, _, Args}) ->
     tuple_type(Args);
+type({args_t, _, Args}) ->
+    args_type(Args);
 type({bytes_t, _, any}) -> text("bytes(_)");
 type({bytes_t, _, Len}) ->
     text(lists:concat(["bytes(", Len, ")"]));
diff --git a/src/aeso_stdlib.erl b/src/aeso_stdlib.erl
index 463697b..8ac47ae 100644
--- a/src/aeso_stdlib.erl
+++ b/src/aeso_stdlib.erl
@@ -10,425 +10,8 @@
 
 -module(aeso_stdlib).
 
--export([stdlib/0, stdlib_list/0, dependencies/1]).
+-export([stdlib_include_path/0]).
 
-stdlib() ->
-    maps:from_list(stdlib_list()).
+stdlib_include_path() ->
+    filename:join([code:priv_dir(aesophia), "stdlib"]).
 
-stdlib_list() ->
-    [ {<<"List.aes">>, std_list()}
-    , {<<"Func.aes">>, std_func()}
-    , {<<"Option.aes">>, std_option()}
-    , {<<"Pair.aes">>, std_pair()}
-    , {<<"Triple.aes">>, std_triple()}
-    ].
-
-dependencies(Q) ->
-    case Q of
-        <<"Option.aes">> ->
-            [<<"List.aes">>];
-        _ -> []
-    end.
-
-std_func() ->
-"
-namespace Func =
-
-  function id(x : 'a) : 'a = x
-
-  function const(x : 'a) : 'b => 'a = (y) => x
-
-  function flip(f : ('a, 'b) => 'c) : ('b, 'a) => 'c = (b, a) => f(a, b)
-
-  function comp(f : 'b => 'c, g : 'a => 'b) : 'a => 'c = (x) => f(g(x))
-
-  function pipe(f : 'a => 'b, g : 'b => 'c) : 'a => 'c = (x) => g(f(x))
-
-  function rapply(x : 'a, f : 'a => 'b) : 'b = f(x)
-
-  /* The Z combinator - replacement for local and anonymous recursion.
-   */
-  function recur(f : ('arg => 'res, 'arg) => 'res) : 'arg => 'res =
-    (x) => f(recur(f), x)
-
-  function iter(n : int, f : 'a => 'a) : 'a => 'a = iter_(n, f, (x) => x)
-  private function iter_(n : int, f : 'a => 'a, acc : 'a => 'a) : 'a => 'a =
-    if(n == 0) acc
-    elif(n == 1) comp(f, acc)
-    else iter_(n / 2, comp(f, f), if(n mod 2 == 0) acc else comp(f, acc))
-
-  function curry2(f : ('a, 'b) => 'c) : 'a => ('b => 'c) =
-    (x) => (y) => f(x, y)
-  function curry3(f : ('a, 'b, 'c) => 'd) : 'a => ('b => ('c => 'd)) =
-    (x) => (y) => (z) => f(x, y, z)
-
-  function uncurry2(f : 'a => ('b => 'c)) : ('a, 'b) => 'c =
-    (x, y) => f(x)(y)
-  function uncurry3(f : 'a => ('b => ('c => 'd))) : ('a, 'b, 'c) => 'd =
-    (x, y, z) => f(x)(y)(z)
-
-  function tuplify2(f : ('a, 'b) => 'c) : (('a * 'b)) => 'c =
-    (t) => switch(t)
-      (x, y) => f(x, y)
-  function tuplify3(f : ('a, 'b, 'c) => 'd) : 'a * 'b * 'c => 'd =
-    (t) => switch(t)
-      (x, y, z) => f(x, y, z)
-
-  function untuplify2(f : 'a * 'b => 'c) : ('a, 'b) => 'c =
-    (x, y) => f((x, y))
-  function untuplify3(f : 'a * 'b * 'c => 'd) : ('a, 'b, 'c) => 'd =
-    (x, y, z) => f((x, y, z))
-".
-
-std_list() ->"
-namespace List =
-
-  function is_empty(l : list('a)) : bool = switch(l)
-    [] => true
-    _  => false
-
-  function first(l : list('a)) : option('a) = switch(l)
-    []   => None
-    h::_ => Some(h)
-
-  function tail(l : list('a)) : option(list('a)) = switch(l)
-    []   => None
-    _::t => Some(t)
-
-  function last(l : list('a)) : option('a) = switch(l)
-    []  => None
-    [x] => Some(x)
-    _::t => last(t)
-
-  function find(p : 'a => bool, l : list('a)) : option('a) = switch(l)
-    []   => None
-    h::t => if(p(h)) Some(h) else find(p, t)
-
-  function find_all(p : 'a => bool, l : list('a)) : list('a) = find_all_(p, l, [])
-  private function find_all_(p : 'a => bool, l : list('a), acc : list('a)) : list('a) = switch(l)
-    []   => reverse(acc)
-    h::t => find_all_(p, t, if(p(h)) h::acc else acc)
-
-  function find_indices(p : 'a => bool, l : list('a)) : list(int) = find_indices_(p, l, 0, [])
-  private function find_indices_( p : 'a => bool
-                                , l : list('a)
-                                , n : int
-                                , acc : list(int)
-                                ) : list(int) = switch(l)
-    []   => reverse(acc)
-    h::t => find_indices_(p, t, n+1, if(p(h)) n::acc else acc)
-
-  function nth(n : int, l : list('a)) : option('a) = switch(l)
-    []   => None
-    h::t => if(n == 0) Some(h) else nth(n-1, t)
-
-  /* Unsafe version of `nth` */
-  function get(n : int, l : list('a)) : 'a = switch(l)
-    [] => abort(\"Out of index get\")
-    h::t => if(n == 0) h else get(n-1, t)
-
-
-  function length(l : list('a)) : int = length_(l, 0)
-  private function length_(l : list('a), acc : int) : int = switch(l)
-    []   => acc
-    _::t => length_(t, acc + 1)
-
-
-  /* Unsafe. Replaces `n`th element of `l` with `e`. Crashes on over/underflow */
-  function replace_at(n : int, e : 'a, l : list('a)) : list('a) =
-    if(n<0) abort(\"insert_at underflow\") else replace_at_(n, e, l, [])
-  private function replace_at_(n : int, e : 'a, l : list('a), acc : list('a)) : list('a) =
-   switch(l)
-     []   => abort(\"replace_at overflow\")
-     h::t => if (n == 0) reverse(e::acc) ++ t
-             else replace_at_(n-1, e, t, h::acc)
-
-  /* Unsafe. Adds `e` to `l` to be its `n`th element. Crashes on over/underflow */
-  function insert_at(n : int, e : 'a, l : list('a)) : list('a) =
-    if(n<0) abort(\"insert_at underflow\") else insert_at_(n, e, l, [])
-  private function insert_at_(n : int, e : 'a, l : list('a), acc : list('a)) : list('a) =
-   if (n == 0) reverse(e::acc) ++ l
-   else switch(l)
-     []   => abort(\"insert_at overflow\")
-     h::t => insert_at_(n-1, e, t, h::acc)
-
-  function insert_by(f : (('a, 'a) => bool), x : 'a, l : list('a)) : list('a) =
-    switch(l)
-      []        => [x]
-      (e :: l') =>
-        if(f(x, e))
-          e :: insert_by(f, x, l')
-        else
-          x :: l
-
-  function foldr(cons : ('a, 'b) => 'b, nil : 'b, l : list('a)) : 'b = switch(l)
-    []   => nil
-    h::t => cons(h, foldr(cons, nil, t))
-
-  function foldl(rcons : ('b, 'a) => 'b, acc : 'b, l : list('a)) : 'b = switch(l)
-    []   => acc
-    h::t => foldl(rcons, rcons(acc, h), t)
-
-  function foreach(f : 'a => unit, l : list('a)) : unit =
-    switch(l)
-     []   => ()
-     e :: l' =>
-       f(e)
-       foreach(f, l')
-
-
-  function reverse(l : list('a)) : list('a) = foldl((lst, el) => el :: lst, [], l)
-
-
-  function map(f : 'a => 'b, l : list('a)) : list('b) = map_(f, l, [])
-  private function map_(f : 'a => 'b, l : list('a), acc : list('b)) : list('b) = switch(l)
-    []   => reverse(acc)
-    h::t => map_(f, t, f(h)::acc)
-
-  function flat_map(f : 'a => list('b), l : list('a)) : list('b) = flat_map_(f, l, [])
-  private function flat_map_(f : 'a => list('b), l : list('a), acc : list('b)) : list('b) = switch(l)
-    []   => reverse(acc)
-    h::t => flat_map_(f, t, reverse(f(h)) ++ acc)
-
-  function filter(p : 'a => bool, l : list('a)) : list('a) = filter_(p, l, [])
-  private function filter_(p : 'a => bool, l : list('a), acc : list('a)) : list('a) = switch(l)
-    []   => reverse(acc)
-    h::t => filter_(p, t, if(p(h)) h::acc else acc)
-
-  /* Take `n` first elements */
-  function take(n : int, l : list('a)) : list('a) =
-    if(n < 0) abort(\"Take negative number of elements\") else take_(n, l, [])
-  private function take_(n : int, l : list('a), acc : list('a)) : list('a) =
-    if(n == 0) reverse(acc)
-    else switch(l)
-      []   => reverse(acc)
-      h::t => take_(n-1, t, h::acc)
-
-  /* Drop `n` first elements */
-  function drop(n : int, l : list('a)) : list('a) =
-   if(n < 0) abort(\"Drop negative number of elements\")
-   elif (n == 0) l
-   else switch(l)
-      []   => []
-      h::t => drop(n-1, t)
-
-  /* Get the longest prefix of a list in which every element matches predicate `p` */
-  function take_while(p : 'a => bool, l : list('a)) : list('a) = take_while_(p, l, [])
-  private function take_while_(p : 'a => bool, l : list('a), acc : list('a)) : list('a) = switch(l)
-    []   => reverse(acc)
-    h::t => if(p(h)) take_while_(p, t, h::acc) else reverse(acc)
-
-  /* Drop elements from `l` until `p` holds */
-  function drop_while(p : 'a => bool, l : list('a)) : list('a) = switch(l)
-    []   => []
-    h::t => if(p(h)) drop_while(p, t) else l
-
-  /* Splits list into two lists of elements that respectively match and don't match predicate `p` */
-  function partition(p : 'a => bool, l : list('a)) : (list('a) * list('a)) = partition_(p, l, [], [])
-  private function partition_( p : 'a => bool
-                             , l : list('a)
-                             , acc_t : list('a)
-                             , acc_f : list('a)
-                             ) : (list('a) * list('a)) = switch(l)
-    []   => (reverse(acc_t), reverse(acc_f))
-    h::t => if(p(h)) partition_(p, t, h::acc_t, acc_f) else partition_(p, t, acc_t, h::acc_f)
-
-
-  function concats(ll : list(list('a))) : list('a) = foldr((l1, l2) => l1 ++ l2, [], ll)
-
-  function all(p : 'a => bool, l : list('a)) : bool = switch(l)
-    []   => true
-    h::t => if(p(h)) all(p, t) else false
-
-  function any(p : 'a => bool, l : list('a)) : bool = switch(l)
-    []   => false
-    h::t => if(p(h)) true else any(p, t)
-
-  function sum(l : list(int)) : int = foldl ((a, b) => a + b, 0, l)
-
-  function product(l : list(int)) : int = foldl((a, b) => a * b, 1, l)
-
-
-  /* Zips two list by applying bimapping function on respective elements. Drops longer tail. */
-  function zip_with(f : ('a, 'b) => 'c, l1 : list('a), l2 : list('b)) : list('c) = zip_with_(f, l1, l2, [])
-  private function zip_with_( f : ('a, 'b) => 'c
-                            , l1 : list('a)
-                            , l2 : list('b)
-                            , acc : list('c)
-                            ) : list('c) = switch ((l1, l2))
-    (h1::t1, h2::t2) => zip_with_(f, t1, t2, f(h1, h2)::acc)
-    _ => reverse(acc)
-
-  /* Zips two lists into list of pairs. Drops longer tail. */
-  function zip(l1 : list('a), l2 : list('b)) : list('a * 'b) = zip_with((a, b) => (a, b), l1, l2)
-
-  function unzip(l : list('a * 'b)) : list('a) * list('b) = unzip_(l, [], [])
-  private function unzip_( l     : list('a * 'b)
-                         , acc_l : list('a)
-                         , acc_r : list('b)
-                         ) : (list('a) * list('b)) = switch(l)
-    []               => (reverse(acc_l), reverse(acc_r))
-    (left, right)::t => unzip_(t, left::acc_l, right::acc_r)
-
-
-  // TODO: Improve?
-  function sort(lesser_cmp : ('a, 'a) => bool, l : list('a)) : list('a) = switch(l)
-    []   => []
-    h::t => switch (partition((x) => lesser_cmp(x, h), t))
-      (lesser, bigger) => sort(lesser_cmp, lesser) ++ h::sort(lesser_cmp, bigger)
-
-
-  function intersperse(delim : 'a, l : list('a)) : list('a) = intersperse_(delim, l, [])
-  private function intersperse_(delim : 'a, l : list('a), acc : list('a)) : list('a) = switch(l)
-    []   => reverse(acc)
-    [e]  => reverse(e::acc)
-    h::t => intersperse_(delim, t, delim::h::acc)
-
-
-  function enumerate(l : list('a)) : list(int * 'a) = enumerate_(l, 0, [])
-  private function enumerate_(l : list('a), n : int, acc : list(int * 'a)) : list(int * 'a) = switch(l)
-    []   => reverse(acc)
-    h::t => enumerate_(t, n + 1, (n, h)::acc)
-
-".
-
-std_option() -> "
-namespace Option =
-
-  function is_none(o : option('a)) : bool = switch(o)
-    None => true
-    Some(_) => false
-
-  function is_some(o : option('a)) : bool = switch(o)
-    None => false
-    Some(_) => true
-
-
-  function match(n : 'b, s : 'a => 'b, o : option('a)) : 'b = switch(o)
-    None => n
-    Some(x) => s(x)
-
-  function default(def : 'a, o : option('a)) : 'a = match(def, (x) => x, o)
-
-  function force(o : option('a)) : 'a = default(abort(\"Forced None value\"), o)
-
-  function on_elem(f : 'a => unit, o : option('a)) : unit = match((), f, o)
-
-
-  function map(f : 'a => 'b, o : option('a)) : option('b) = switch(o)
-    None => None
-    Some(x) => Some(f(x))
-
-  function map2(f : ('a, 'b) => 'c
-               , o1 : option('a)
-               , o2 : option('b)
-               ) : option('c) = switch((o1, o2))
-    (Some(x1), Some(x2)) => Some(f(x1, x2))
-    _ => None
-
-  function map3( f : ('a, 'b, 'c) => 'd
-               , o1 : option('a)
-               , o2 : option('b)
-               , o3 : option('c)
-               ) : option('d) = switch((o1, o2, o3))
-    (Some(x1), Some(x2), Some(x3)) => Some(f(x1, x2, x3))
-    _ => None
-
-  function app_over(f : option ('a => 'b), o : option('a)) : option('b) = switch((f, o))
-    (Some(ff), Some(xx)) => Some(ff(xx))
-    _ => None
-
-  function flat_map(f : 'a => option('b), o : option('a)) : option('b) = switch(o)
-    None => None
-    Some(x) => f(x)
-
-
-  function to_list(o : option('a)) : list('a) = switch(o)
-    None => []
-    Some(x) => [x]
-
-  function filter_options(l : list(option('a))) : list('a) = filter_options_(l, [])
-  private function filter_options_(l : list (option('a)), acc : list('a)) : list('a) = switch(l)
-    []         => List.reverse(acc)
-    None::t    => filter_options_(t, acc)
-    Some(x)::t => filter_options_(t, x::acc)
-
-  function seq_options(l : list (option('a))) : option (list('a)) = seq_options_(l, [])
-  private function seq_options_(l : list (option('a)), acc : list('a)) : option(list('a)) = switch(l)
-    []         => Some(List.reverse(acc))
-    None::t    => None
-    Some(x)::t => seq_options_(t, x::acc)
-
-
-  function choose(o1 : option('a), o2 : option('a)) : option('a) =
-    if(is_some(o1)) o1 else o2
-
-  function choose_first(l : list(option('a))) : option('a) = switch(l)
-    [] => None
-    None::t    => choose_first(t)
-    Some(x)::_ => Some(x)
-".
-
-std_pair() -> "
-namespace Pair =
-
-  function fst(t : ('a * 'b)) : 'a = switch(t)
-    (x, _) => x
-
-  function snd(t : ('a * 'b)) : 'b = switch(t)
-    (_, y) => y
-
-
-  function map1(f : 'a => 'c, t : ('a * 'b)) : ('c * 'b) = switch(t)
-    (x, y) => (f(x), y)
-
-  function map2(f : 'b => 'c, t : ('a * 'b)) : ('a * 'c) = switch(t)
-    (x, y) => (x, f(y))
-
-  function bimap(f : 'a => 'c, g : 'b => 'd, t : ('a * 'b)) : ('c * 'd) = switch(t)
-    (x, y) => (f(x), g(y))
-
-
-  function swap(t : ('a * 'b)) : ('b * 'a) = switch(t)
-    (x, y) => (y, x)
-".
-
-std_triple() -> "
-namespace Triple =
-
-  function fst(t : ('a * 'b * 'c)) : 'a = switch(t)
-    (x, _, _) => x
-
-  function snd(t : ('a * 'b * 'c)) : 'b = switch(t)
-    (_, y, _) => y
-
-  function thd(t : ('a * 'b * 'c)) : 'c = switch(t)
-    (_, _, z) => z
-
-
-  function map1(f : 'a => 'm, t : ('a * 'b * 'c)) : ('m * 'b * 'c) = switch(t)
-    (x, y, z) => (f(x), y, z)
-
-  function map2(f : 'b => 'm, t : ('a * 'b * 'c)) : ('a * 'm * 'c) = switch(t)
-    (x, y, z) => (x, f(y), z)
-
-  function map3(f : 'c => 'm, t : ('a * 'b * 'c)) : ('a * 'b * 'm) = switch(t)
-    (x, y, z) => (x, y, f(z))
-
-  function trimap( f : 'a => 'x
-                 , g : 'b => 'y
-                 , h : 'c => 'z
-                 , t : ('a * 'b * 'c)
-                 ) : ('x * 'y * 'z) = switch(t)
-    (x, y, z) => (f(x), g(y), h(z))
-
-
-  function swap(t : ('a * 'b * 'c)) : ('c * 'b * 'a) = switch(t)
-    (x, y, z) => (z, y, x)
-
-  function rotr(t : ('a * 'b * 'c)) : ('c * 'a * 'b) = switch(t)
-    (x, y, z) => (z, x, y)
-
-  function rotl(t : ('a * 'b * 'c)) : ('b * 'c * 'a) = switch(t)
-    (x, y, z) => (y, z, x)
-".
diff --git a/src/aeso_syntax.erl b/src/aeso_syntax.erl
index 403dfaa..2e9f69a 100644
--- a/src/aeso_syntax.erl
+++ b/src/aeso_syntax.erl
@@ -59,6 +59,7 @@
 -type type() :: {fun_t, ann(), [named_arg_t()], [type()], type()}
               | {app_t, ann(), type(), [type()]}
               | {tuple_t, ann(), [type()]}
+              | {args_t, ann(), [type()]}   %% old tuple syntax, old for error messages
               | {bytes_t, ann(), integer() | any}
               | id()  | qid()
               | con() | qcon()  %% contracts
@@ -105,9 +106,9 @@
      | id() | qid() | con() | qcon()
      | constant().
 
--type comprehension_exp() :: [{ comprehension_bind, ann(), id(), expr()}
-                             | {comprehension_if, expr()}
-                             | letbind()].
+-type comprehension_exp() :: [ {comprehension_bind, id(), expr()}
+                             | {comprehension_if, ann(), expr()}
+                             | letbind() ].
 
 -type arg_expr() :: expr() | {named_arg, ann(), id(), expr()}.
 
diff --git a/src/aeso_syntax_utils.erl b/src/aeso_syntax_utils.erl
index f2d2fac..5aa43e9 100644
--- a/src/aeso_syntax_utils.erl
+++ b/src/aeso_syntax_utils.erl
@@ -49,7 +49,7 @@ fold(Alg = #alg{zero = Zero, plus = Plus, scoped = Scoped}, Fun, K, X) ->
             {type_def, _, I, _, D}   -> Plus(BindType(I), Decl(D));
             {fun_decl, _, _, T}      -> Type(T);
             {letval, _, F, T, E}     -> Sum([BindExpr(F), Type(T), Expr(E)]);
-            {letfun, _, F, Xs, T, E} -> Sum([BindExpr(F), Type(T), Scoped(BindExpr(Xs), Expr(E))]);
+            {letfun, _, F, Xs, T, E} -> Sum([BindExpr(F), Type(T), Expr(Xs ++ [E])]);
             %% typedef()
             {alias_t, T}    -> Type(T);
             {record_t, Fs}  -> Type(Fs);
@@ -74,7 +74,7 @@ fold(Alg = #alg{zero = Zero, plus = Plus, scoped = Scoped}, Fun, K, X) ->
             {list_comp, _, Y, []}  -> Expr(Y);
             {list_comp, A, Y, [{comprehension_bind, I, E}|R]} ->
                 Plus(Expr(E), Scoped(BindExpr(I), Expr({list_comp, A, Y, R})));
-            {list_comp, A, Y, [{comprehension_if, E}|R]} ->
+            {list_comp, A, Y, [{comprehension_if, _, E}|R]} ->
                 Plus(Expr(E), Expr({list_comp, A, Y, R}));
             {list_comp, A, Y, [D = {letval, _, F, _, _} | R]} ->
                 Plus(Decl(D), Scoped(BindExpr(F), Expr({list_comp, A, Y, R})));
@@ -92,7 +92,7 @@ fold(Alg = #alg{zero = Zero, plus = Plus, scoped = Scoped}, Fun, K, X) ->
             {field, _, LV, E}    -> Expr([LV, E]);
             {field, _, LV, _, E} -> Expr([LV, E]);
             %% arg()
-            {arg, _, X, T} -> Plus(Expr(X), Type(T));
+            {arg, _, Y, T} -> Plus(BindExpr(Y), Type(T));
             %% alt()
             {'case', _, P, E} -> Scoped(BindExpr(P), Expr(E));
             %% elim()
@@ -124,12 +124,12 @@ used_types([Top] = _CurrentNS, T) ->
 entity_alg() ->
     IsBound = fun({K, _}) -> lists:member(K, [bound_term, bound_type]) end,
     Unbind  = fun(bound_term) -> term; (bound_type) -> type end,
-    Remove  = fun(Keys, Map) -> lists:foldl(fun maps:remove/2, Map, Keys) end,
+    Remove  = fun(Keys, Map) -> maps:without(Keys, Map) end,
     Scoped = fun(Xs, Ys) ->
-                Bound  = [E || E <- maps:keys(Ys), IsBound(E)],
-                Others = Remove(Bound, Ys),
+                Bound  = [E || E <- maps:keys(Xs), IsBound(E)],
                 Bound1 = [ {Unbind(Tag), X} || {Tag, X} <- Bound ],
-                maps:merge(Remove(Bound1, Xs), Others)
+                Others = Remove(Bound1, Ys),
+                maps:merge(Remove(Bound, Xs), Others)
             end,
     #alg{ zero   = #{}
         , plus   = fun maps:merge/2
diff --git a/test/aeso_abi_tests.erl b/test/aeso_abi_tests.erl
index 9d0a022..c6ce469 100644
--- a/test/aeso_abi_tests.erl
+++ b/test/aeso_abi_tests.erl
@@ -80,11 +80,11 @@ encode_decode_sophia_string(SophiaType, String) ->
            , "  record r = {x : an_alias(int), y : variant}\n"
            , "  datatype variant = Red | Blue(map(string, int))\n"
            , "  entrypoint foo : arg_type => arg_type\n" ],
-    case aeso_compiler:check_call(lists:flatten(Code), "foo", [String], [no_implicit_stdlib]) of
+    case aeso_compiler:check_call(lists:flatten(Code), "foo", [String], []) of
         {ok, _, {[Type], _}, [Arg]} ->
             io:format("Type ~p~n", [Type]),
             Data = encode(Arg),
-            case aeso_compiler:to_sophia_value(Code, "foo", ok, Data, [no_implicit_stdlib]) of
+            case aeso_compiler:to_sophia_value(Code, "foo", ok, Data, []) of
                 {ok, Sophia} ->
                     lists:flatten(io_lib:format("~s", [prettypr:format(aeso_pretty:expr(Sophia))]));
                 {error, Err} ->
@@ -152,7 +152,7 @@ oracle_test() ->
         "    Oracle.get_question(o, q)\n",
     {ok, _, {[word, word], {list, string}}, [16#123, 16#456]} =
         aeso_compiler:check_call(Contract, "question", ["ok_111111111111111111111111111111ZrdqRz9",
-                                                        "oq_1111111111111111111111111111113AFEFpt5"], [no_implicit_stdlib]),
+                                                        "oq_1111111111111111111111111111113AFEFpt5"], []),
 
     ok.
 
@@ -162,7 +162,7 @@ permissive_literals_fail_test() ->
         "  stateful entrypoint haxx(o : oracle(list(string), option(int))) =\n"
         "    Chain.spend(o, 1000000)\n",
         {error, <<"Type errors\nCannot unify", _/binary>>} =
-            aeso_compiler:check_call(Contract, "haxx", ["#123"], [no_implicit_stdlib]),
+            aeso_compiler:check_call(Contract, "haxx", ["#123"], []),
     ok.
 
 encode_decode_calldata(FunName, Types, Args) ->
@@ -173,8 +173,8 @@ encode_decode_calldata(FunName, Types, Args, RetType) ->
     encode_decode_calldata_(Code, FunName, Args, RetType).
 
 encode_decode_calldata_(Code, FunName, Args, RetVMType) ->
-    {ok, Calldata} = aeso_compiler:create_calldata(Code, FunName, Args, [no_implicit_stdlib]),
-    {ok, _, {ArgTypes, RetType}, _} = aeso_compiler:check_call(Code, FunName, Args, [{backend, aevm}, no_implicit_stdlib]),
+    {ok, Calldata} = aeso_compiler:create_calldata(Code, FunName, Args, []),
+    {ok, _, {ArgTypes, RetType}, _} = aeso_compiler:check_call(Code, FunName, Args, [{backend, aevm}]),
     ?assertEqual(RetType, RetVMType),
     CalldataType = {tuple, [word, {tuple, ArgTypes}]},
     {ok, {_Hash, ArgTuple}} = aeb_heap:from_binary(CalldataType, Calldata),
@@ -182,7 +182,7 @@ encode_decode_calldata_(Code, FunName, Args, RetVMType) ->
         "init" ->
             ok;
         _ ->
-            {ok, _ArgTypes, ValueASTs} = aeso_compiler:decode_calldata(Code, FunName, Calldata, [no_implicit_stdlib]),
+            {ok, _ArgTypes, ValueASTs} = aeso_compiler:decode_calldata(Code, FunName, Calldata, []),
             Values = [ prettypr:format(aeso_pretty:expr(V)) || V <- ValueASTs ],
             ?assertMatch({X, X}, {Args, Values})
     end,
diff --git a/test/aeso_aci_tests.erl b/test/aeso_aci_tests.erl
index 18cb499..eee30ae 100644
--- a/test/aeso_aci_tests.erl
+++ b/test/aeso_aci_tests.erl
@@ -9,7 +9,7 @@ simple_aci_test_() ->
 
 test_contract(N) ->
     {Contract,MapACI,DecACI} = test_cases(N),
-    {ok,JSON} = aeso_aci:contract_interface(json, Contract, [no_implicit_stdlib]),
+    {ok,JSON} = aeso_aci:contract_interface(json, Contract),
     ?assertEqual([MapACI], JSON),
     ?assertEqual({ok, DecACI}, aeso_aci:render_aci_json(JSON)).
 
@@ -90,8 +90,7 @@ aci_test_() ->
       fun() -> aci_test_contract(ContractName) end}
      || ContractName <- all_contracts()].
 
-all_contracts() -> [C || C <- aeso_compiler_tests:compilable_contracts()
-                             , not aeso_compiler_tests:wants_stdlib(C)].
+all_contracts() -> aeso_compiler_tests:compilable_contracts().
 
 aci_test_contract(Name) ->
     String = aeso_test_utils:read_contract(Name),
diff --git a/test/aeso_calldata_tests.erl b/test/aeso_calldata_tests.erl
index aa732a7..2f419cc 100644
--- a/test/aeso_calldata_tests.erl
+++ b/test/aeso_calldata_tests.erl
@@ -21,14 +21,12 @@ calldata_test_() ->
            ContractString = aeso_test_utils:read_contract(ContractName),
            AevmExprs =
               case not lists:member(ContractName, not_yet_compilable(aevm)) of
-                  true -> ast_exprs(ContractString, Fun, Args, [{backend, aevm}]
-                                    ++ [no_implicit_stdlib || not aeso_compiler_tests:wants_stdlib(ContractName)]);
+                  true -> ast_exprs(ContractString, Fun, Args, [{backend, aevm}]);
                   false -> undefined
               end,
            FateExprs =
               case not lists:member(ContractName, not_yet_compilable(fate)) of
-                  true -> ast_exprs(ContractString, Fun, Args, [{backend, fate}]
-                                    ++ [no_implicit_stdlib || not aeso_compiler_tests:wants_stdlib(ContractName)]);
+                  true -> ast_exprs(ContractString, Fun, Args, [{backend, fate}]);
                   false -> undefined
               end,
            case FateExprs == undefined orelse AevmExprs == undefined of
@@ -47,14 +45,12 @@ calldata_aci_test_() ->
            io:format("ACI:\n~s\n", [ContractACIBin]),
            AevmExprs =
               case not lists:member(ContractName, not_yet_compilable(aevm)) of
-                  true -> ast_exprs(ContractACI, Fun, Args, [{backend, aevm}]
-                                    ++ [no_implicit_stdlib || not aeso_compiler_tests:wants_stdlib(ContractName)]);
+                  true -> ast_exprs(ContractACI, Fun, Args, [{backend, aevm}]);
                   false -> undefined
               end,
            FateExprs =
               case not lists:member(ContractName, not_yet_compilable(fate)) of
-                  true -> ast_exprs(ContractACI, Fun, Args, [{backend, fate}]
-                                    ++ [no_implicit_stdlib || not aeso_compiler_tests:wants_stdlib(ContractName)]);
+                  true -> ast_exprs(ContractACI, Fun, Args, [{backend, fate}]);
                   false -> undefined
               end,
            case FateExprs == undefined orelse AevmExprs == undefined of
diff --git a/test/aeso_compiler_tests.erl b/test/aeso_compiler_tests.erl
index 9a9f743..6ba37e1 100644
--- a/test/aeso_compiler_tests.erl
+++ b/test/aeso_compiler_tests.erl
@@ -76,8 +76,7 @@ check_errors(Expect, ErrorString) ->
 
 compile(Backend, Name) ->
     compile(Backend, Name,
-            [{include, {file_system, [aeso_test_utils:contract_path()]}}]
-            ++ [no_implicit_stdlib || not wants_stdlib(Name)]).
+            [{include, {file_system, [aeso_test_utils:contract_path()]}}]).
 
 compile(Backend, Name, Options) ->
     String = aeso_test_utils:read_contract(Name),
@@ -375,12 +374,3 @@ failing_contracts() ->
       ]}
     ].
 
-wants_stdlib(Name) ->
-    lists:member
-      (Name,
-       [ "stdlib_include",
-         "list_comp",
-         "list_comp_not_a_list",
-         "list_comp_if_not_bool",
-         "list_comp_bad_shadow"
-       ]).
diff --git a/test/aeso_parser_tests.erl b/test/aeso_parser_tests.erl
index 9b54d94..ea6c517 100644
--- a/test/aeso_parser_tests.erl
+++ b/test/aeso_parser_tests.erl
@@ -15,7 +15,7 @@ simple_contracts_test_() ->
             ?assertMatch(
                 [{contract, _, {con, _, "Identity"},
                     [{letfun, _, {id, _, "id"}, [{arg, _, {id, _, "x"}, {id, _, "_"}}], {id, _, "_"},
-                        {id, _, "x"}}]}], parse_string(Text, [no_implicit_stdlib])),
+                        {id, _, "x"}}]}], parse_string(Text)),
             ok
        end},
       {"Operator precedence test.",
@@ -81,17 +81,21 @@ parse_string(Text, Opts) ->
 
 parse_expr(Text) ->
     [{letval, _, _, _, Expr}] =
-        parse_string("let _ = " ++ Text, [no_implicit_stdlib]),
+        parse_string("let _ = " ++ Text),
     Expr.
 
 round_trip(Text) ->
-    Contract  = parse_string(Text, [no_implicit_stdlib]),
-    Text1     = prettypr:format(aeso_pretty:decls(Contract)),
-    Contract1 = parse_string(Text1, [no_implicit_stdlib]),
+    Contract  = parse_string(Text),
+    Text1     = prettypr:format(aeso_pretty:decls(strip_stdlib(Contract))),
+    Contract1 = parse_string(Text1),
     NoSrcLoc  = remove_line_numbers(Contract),
     NoSrcLoc1 = remove_line_numbers(Contract1),
     ?assertMatch(NoSrcLoc, diff(NoSrcLoc, NoSrcLoc1)).
 
+strip_stdlib([{namespace, _, {con, _, "ListInternal"}, _} | Decls]) ->
+    strip_stdlib(Decls);
+strip_stdlib(Decls) -> Decls.
+
 remove_line_numbers({line, _L}) -> {line, 0};
 remove_line_numbers({col,  _C}) -> {col, 0};
 remove_line_numbers([H|T]) ->
diff --git a/test/contracts/list_comp.aes b/test/contracts/list_comp.aes
index 266f2e8..db98bb5 100644
--- a/test/contracts/list_comp.aes
+++ b/test/contracts/list_comp.aes
@@ -10,11 +10,11 @@ contract ListComp =
     entrypoint l2_true() = [5,6,6,7,7,8]
 
     entrypoint l3() = [x ++ y | x <- [[":)"] | x <- [1,2]]
-                              , y <- [[":("]]]  
+                              , y <- [[":("]]]
     entrypoint l3_true() = [[":)", ":("], [":)", ":("]]
 
     entrypoint l4() = [(a, b, c) | let is_pit(a, b, c) = a*a + b*b == c*c
-                                 , let base = [1,2,3,4,5,6,7,8,9,10]
+                                 , let base = [1..10]
                                  , a <- base
                                  , b <- base, if (b >= a)
                                  , c <- base, if (c >= b)
diff --git a/test/contracts/manual_stdlib_include.aes b/test/contracts/manual_stdlib_include.aes
index 5937c37..76a896e 100644
--- a/test/contracts/manual_stdlib_include.aes
+++ b/test/contracts/manual_stdlib_include.aes
@@ -1,5 +1,4 @@
-// This contract should be compiled with no_implicit_stdlib option.
-// It should include Lists.aes implicitly however, because Option.aes depends on it.
+// This should include Lists.aes implicitly, since Option.aes does.
 include "Option.aes"
 
 contract Test =
diff --git a/test/contracts/stdlib_include.aes b/test/contracts/stdlib_include.aes
index 6149db2..d890ae8 100644
--- a/test/contracts/stdlib_include.aes
+++ b/test/contracts/stdlib_include.aes
@@ -1,3 +1,6 @@
+include "List.aes"
+include "Func.aes"
+
 contract StdInc =
   entrypoint test() = List.map((x) => Func.id(x), [1,2,3,4])