Second try: Fix resolution and canonicalization of typedefs and function types

runtime/vm/parser.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/parser.h"
 #include "vm/flags.h"
 
 #ifndef DART_PRECOMPILED_RUNTIME
 
 #include "lib/invocation_mirror.h"
@@ skipping 2037 matching lines @@
     if (!var_seen && !final_seen) {
       // The parsed parameter type is actually the function result type.
       AbstractType& result_type =
           AbstractType::Handle(Z, parameter.type->raw());
 
       // In top-level and mixin functions, the source may be in a different
       // script than the script of the current class. However, we never reparse
       // signature functions (except typedef signature functions), therefore
       // we do not need to keep the correct script via a patch class. Use the
       // actual current class as owner of the signature function.
-      const Function& signature_function =
+      Function& signature_function =
           Function::Handle(Z, Function::NewSignatureFunction(
                                   current_class(), TokenPosition::kNoSource));
       signature_function.set_parent_function(innermost_function());
       innermost_function_ = signature_function.raw();
 
       // Finish parsing the function type parameter.
       if (CurrentToken() == Token::kLT) {
         if (!FLAG_generic_method_syntax) {
           ReportError("generic function types not supported");
         }
@@ skipping 19 matching lines @@
       AddFormalParamsToFunction(&func_params, signature_function);
 
       ASSERT(innermost_function().raw() == signature_function.raw());
       innermost_function_ = signature_function.parent_function();
 
       Type& signature_type =
           Type::ZoneHandle(Z, signature_function.SignatureType());
       if (!is_top_level_) {
         signature_type ^= ClassFinalizer::FinalizeType(
             current_class(), signature_type, ClassFinalizer::kCanonicalize);
-        signature_function.SetSignatureType(signature_type);
+        // Do not refer to signature_function anymore, since it may have been
+        // replaced during canonicalization.
+        signature_function = Function::null();
       }
       ASSERT(is_top_level_ || signature_type.IsFinalized());
       // A signature type itself cannot be malformed or malbounded, only its
       // signature function's result type or parameter types may be.
       ASSERT(!signature_type.IsMalformed());
       ASSERT(!signature_type.IsMalbounded());
       // The type of the parameter is now the signature type.
       parameter.type = &signature_type;
     }
   } else {
@@ skipping 9777 matching lines @@
   }
   return expr;
 }
 
 
 // Resolve the given type and its type arguments from the current function and
 // current class according to the given type finalization mode.
 // Not all involved type classes may get resolved yet, but at least type
 // parameters will get resolved, thereby relieving the class
 // finalizer from resolving type parameters out of context.
+// TODO(regis): Refactor this code which is partially duplicated in the class
+// finalizer, paying attention to type parameter resolution and mixin library.
 void Parser::ResolveType(ClassFinalizer::FinalizationKind finalization,
                          AbstractType* type) {
   ASSERT(finalization >= ClassFinalizer::kResolveTypeParameters);
   ASSERT(type != NULL);
   if (type->IsResolved()) {
     return;
   }
   // Resolve class.
   if (!type->HasResolvedTypeClass()) {
     const UnresolvedClass& unresolved_class =
@@ skipping 57 matching lines @@
           Object::Handle(Z, unresolved_class.library_or_library_prefix());
       ASSERT(prefix.IsLibraryPrefix());
       resolved_type_class =
           LibraryPrefix::Cast(prefix).LookupClass(unresolved_class_name);
     }
     // At this point, we can only have a parameterized_type.
     const Type& parameterized_type = Type::Cast(*type);
     if (!resolved_type_class.IsNull()) {
       // Replace unresolved class with resolved type class.
       parameterized_type.set_type_class(resolved_type_class);
+      // Promote type to a function type in case its type class is a typedef.
+      if (resolved_type_class.IsTypedefClass()) {
+        ASSERT(!parameterized_type.IsFunctionType());
+        parameterized_type.set_signature(
+            Function::Handle(Z, resolved_type_class.signature_function()));
+      }
     } else if (finalization >= ClassFinalizer::kCanonicalize) {
       ClassFinalizer::FinalizeMalformedType(
           Error::Handle(Z),  // No previous error.
           script_, parameterized_type, "type '%s' is not loaded",
           String::Handle(Z, parameterized_type.UserVisibleName()).ToCString());
       return;
     }
   }
+  if (finalization > ClassFinalizer::kResolveTypeParameters) {
+    type->SetIsResolved();
+  }
   // Resolve type arguments, if any.
   if (type->arguments() != TypeArguments::null()) {
     const TypeArguments& arguments =
         TypeArguments::Handle(Z, type->arguments());
     const intptr_t num_arguments = arguments.Length();
     AbstractType& type_argument = AbstractType::Handle(Z);
     for (intptr_t i = 0; i < num_arguments; i++) {
       type_argument ^= arguments.TypeAt(i);
       ResolveType(finalization, &type_argument);
       arguments.SetTypeAt(i, type_argument);
     }
   }
+  if (type->IsFunctionType()) {
+    const Function& signature =
+        Function::Handle(Z, Type::Cast(*type).signature());
+    Type& signature_type = Type::Handle(Z, signature.SignatureType());
+    if (signature_type.raw() != type->raw()) {
+      ResolveType(finalization, &signature_type);
+    } else {
+      AbstractType& type = AbstractType::Handle(signature.result_type());
+      ResolveType(finalization, &type);
+      signature.set_result_type(type);
+      const intptr_t num_parameters = signature.NumParameters();
+      for (intptr_t i = 0; i < num_parameters; i++) {
+        type = signature.ParameterTypeAt(i);
+        ResolveType(finalization, &type);
+        signature.SetParameterTypeAt(i, type);
+      }
+      if (signature.IsSignatureFunction()) {
+        // Drop fields that are not necessary anymore after resolution.
+        // The parent function, owner, and token position of a shared
+        // canonical function type are meaningless, since the canonical
+        // representent is picked arbitrarily.
+        signature.set_parent_function(Function::Handle(Z));
+        // TODO(regis): As long as we support metadata in typedef signatures,
+        // we cannot reset these fields used to reparse a typedef.
+        // Note that the scope class of a typedef function type is always
+        // preserved as the typedef class (not reset to _Closure class), thereby
+        // preventing sharing of canonical function types between typedefs.
+        // Not being shared, these fields are therefore always meaningful for
+        // typedefs.
+        if (type.HasResolvedTypeClass()) {

[regis, 2016/12/28 22:12:18]

This ResolveType function may be called with finalization ==
ClassFinalizer::kResolveTypeParameters, in which case the type class is not yet
resolved at this point. The class finalizer will resolve and check it later.

+          const Class& scope_class = Class::Handle(Z, type.type_class());
+          if (!scope_class.IsTypedefClass()) {
+            signature.set_owner(Object::Handle(Z));
+            signature.set_token_pos(TokenPosition::kNoSource);
+          }
+        }
+      }
+    }
+  }
 }
 
 
 LocalVariable* Parser::LookupLocalScope(const String& ident) {
   if (current_block_ == NULL) {
     return NULL;
   }
   // A found name is treated as accessed and possibly marked as captured.
   const bool kTestOnly = false;
   return current_block_->scope->LookupVariable(ident, kTestOnly);
@@ skipping 2539 matching lines @@
     const ArgumentListNode& function_args,
     const LocalVariable* temp_for_last_arg,
     bool is_super_invocation) {
   UNREACHABLE();
   return NULL;
 }
 
 }  // namespace dart
 
 #endif  // DART_PRECOMPILED_RUNTIME