src/aeso_ast_infer_types.erl

@@ -1138,7 +1138,7 @@ infer_expr(Env, {list, As, Elems}) ->
     NewElems = [check_expr(Env, X, ElemType) || X <- Elems],
     {typed, As, {list, As, NewElems}, {app_t, As, {id, As, "list"}, [ElemType]}};
 infer_expr(Env, {list_comp, As, Yield, []}) ->
-    {typed, _, TypedYield, Type} = infer_expr(Env, Yield),
+    {typed, _, _, Type} = TypedYield = infer_expr(Env, Yield),
     {typed, As, {list_comp, As, TypedYield, []}, {app_t, As, {id, As, "list"}, [Type]}};
 infer_expr(Env, {list_comp, As, Yield, [{comprehension_bind, Arg, BExpr}|Rest]}) ->
     BindVarType = fresh_uvar(As),

src/aeso_pretty.erl

@@ -305,6 +305,8 @@ expr_p(_, {tuple, _, Es}) ->
     tuple(lists:map(fun expr/1, Es));
 expr_p(_, {list, _, Es}) ->
     list(lists:map(fun expr/1, Es));
+expr_p(_, {list_comp, _, E, Binds}) ->
+    list([follow(expr(E), hsep(text("|"), par(punctuate(text(","), lists:map(fun lc_bind/1, Binds)), 0)), 0)]);
 expr_p(_, {record, _, Fs}) ->
     record(lists:map(fun field/1, Fs));
 expr_p(_, {map, Ann, KVs}) ->
@@ -387,6 +389,13 @@ stmt_p({else, Else}) ->
         _ -> block_expr(200, text("else"), Else)
     end.
 
+lc_bind({comprehension_bind, P, E}) ->
+    follow(hsep(expr(P), text("<-")), expr(E));
+lc_bind({comprehension_if, _, E}) ->
+    beside([text("if("), expr(E), text(")")]);
+lc_bind(Let) ->
+    letdecl("let", Let).
+
 -spec bin_prec(aeso_syntax:bin_op()) -> {integer(), integer(), integer()}.
 bin_prec('..')   -> {  0,   0,   0};  %% Always printed inside '[ ]'
 bin_prec('=')    -> {  0,   0,   0};  %% Always printed inside '[ ]'

test/aeso_compiler_tests.erl

@@ -138,6 +138,7 @@ compilable_contracts() ->
      "test",
      "builtin_bug",
      "builtin_map_get_bug",
+     "lc_record_bug",
      "nodeadcode",
      "deadcode",
      "variant_types",

test/contracts/lc_record_bug.aes

@@ -0,0 +1,4 @@
+contract Foo =
+  record r = {x : int}
+  // Crashed in the backend due to missing type annotation on the lc body.
+  entrypoint lc(xs) = [ {x = x} | x <- xs ]