Revert "Fix resolution and canonicalization of typedefs and function types..."

runtime/vm/class_finalizer.cc

Index: runtime/vm/class_finalizer.cc
diff --git a/runtime/vm/class_finalizer.cc b/runtime/vm/class_finalizer.cc
index adf967e79ecef0c1fe8d04285cdf2d0cd911c4c6..f13d562061ef4a27dbfcfa430baea9bc8c33593c 100644
--- a/runtime/vm/class_finalizer.cc
+++ b/runtime/vm/class_finalizer.cc
@@ -549,34 +549,11 @@ void ClassFinalizer::ResolveType(const Class& cls, const AbstractType& type) {
   // Resolve signature if function type.
   if (type.IsFunctionType()) {
     const Function& signature = Function::Handle(Type::Cast(type).signature());
-    Type& signature_type = Type::Handle(signature.SignatureType());
-    if (signature_type.raw() != type.raw()) {
-      ResolveType(cls, signature_type);
+    const Class& scope_class = Class::Handle(type.type_class());
+    if (scope_class.IsTypedefClass()) {
+      ResolveSignature(scope_class, signature);
     } else {
-      const Class& scope_class = Class::Handle(type.type_class());
-      if (scope_class.IsTypedefClass()) {
-        ResolveSignature(scope_class, signature);
-      } else {
-        ResolveSignature(cls, signature);
-      }
-      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());
-        // 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 (!scope_class.IsTypedefClass()) {
-          signature.set_owner(Object::Handle());
-          signature.set_token_pos(TokenPosition::kNoSource);
-        }
-      }
+      ResolveSignature(cls, signature);
     }
   }
 }
@@ -2354,9 +2331,8 @@ void ClassFinalizer::FinalizeTypesInClass(const Class& cls) {
     cls.set_mixin(mixin_type);
   }
   if (cls.IsTypedefClass()) {
-    Function& signature = Function::Handle(cls.signature_function());
+    const Function& signature = Function::Handle(cls.signature_function());
     Type& type = Type::Handle(signature.SignatureType());
-    ASSERT(type.signature() == signature.raw());
 
     // Check for illegal self references.
     GrowableArray<intptr_t> visited_aliases;
@@ -2374,12 +2350,7 @@ void ClassFinalizer::FinalizeTypesInClass(const Class& cls) {
 
     // Resolve and finalize the signature type of this typedef.
     type ^= FinalizeType(cls, type, kCanonicalizeWellFormed);
-
-    // If a different canonical signature type is returned, update the signature
-    // function of the typedef.
-    signature = type.signature();
     signature.SetSignatureType(type);
-    cls.set_signature_function(signature);
 
     // Closure instances do not refer to this typedef as their class, so there
     // is no need to add this typedef class to the subclasses of _Closure.