Adjust assertions in MethodMirror.source not to expect source for implicit constructors or signatur…

runtime/lib/mirrors.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 "lib/invocation_mirror.h"
 #include "vm/bootstrap_natives.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
 #include "vm/exceptions.h"
@@ skipping 2019 matching lines @@
   // We handle constructors in Dart code.
   ASSERT(!func.IsConstructor());
   const AbstractType& type = AbstractType::Handle(func.result_type());
   return InstantiateType(type, instantiator);
 }
 
 
 DEFINE_NATIVE_ENTRY(MethodMirror_source, 1) {
   GET_NON_NULL_NATIVE_ARGUMENT(MirrorReference, ref, arguments->NativeArgAt(0));
   const Function& func = Function::Handle(ref.GetFunctionReferent());
+  if (func.IsImplicitConstructor() || func.IsSignatureFunction()) {

[hausner, 2014/02/07 21:07:58]

There may be other cases of functions that have no source code. I can think of
the forwarding constructors that are inserted in mixin application classes, or
implicit getter and setter functions, method extractor functions, no such method
dispatcher. Can these functions appear here?

[rmacnak, 2014/02/07 21:28:46]

Now it is considered an implicit constructor. Leaving a note that that might
change when the restrictions on mixins are relaxed.
No, we don't hand out mirrors on these.

+    return Instance::null();
+  }
   const Script& script = Script::Handle(func.script());
   const TokenStream& stream = TokenStream::Handle(script.tokens());
   const TokenStream::Iterator tkit(stream, func.end_token_pos());
   intptr_t from_line;
   intptr_t from_col;
   intptr_t to_line;
   intptr_t to_col;
   script.GetTokenLocation(func.token_pos(), &from_line, &from_col);
   script.GetTokenLocation(func.end_token_pos(), &to_line, &to_col);
   intptr_t last_tok_len = String::Handle(tkit.CurrentLiteral()).Length();
   // Handle special cases for end tokens of closures (where we exclude the last
   // token):
   // (1) "foo(() => null, bar);": End token is `,', but we don't print it.
   // (2) "foo(() => null);": End token is ')`, but we don't print it.
   // (3) "var foo = () => null;": End token is `;', but in this case the token
   // semicolon belongs to the assignment so we skip it.
   if ((tkit.CurrentTokenKind() == Token::kCOMMA) ||                   // Case 1.
       (tkit.CurrentTokenKind() == Token::kRPAREN) ||                  // Case 2.
       (tkit.CurrentTokenKind() == Token::kSEMICOLON &&
        String::Handle(func.name()).Equals("<anonymous closure>"))) {  // Case 3.
     last_tok_len = 0;
   }
-  return script.GetSnippet(from_line, from_col, to_line, to_col + last_tok_len);
+  const Instance& result = Instance::Handle(
+      script.GetSnippet(from_line, from_col, to_line, to_col + last_tok_len));
+  ASSERT(!result.IsNull());
+  return result.raw();
 }
 
 
 DEFINE_NATIVE_ENTRY(TypedefMirror_referent, 1) {
   GET_NON_NULL_NATIVE_ARGUMENT(Type, type, arguments->NativeArgAt(0));
   const Class& cls = Class::Handle(type.type_class());
   const Function& sig_func = Function::Handle(cls.signature_function());
   const Class& sig_cls = Class::Handle(sig_func.signature_class());
 
   AbstractType& referent_type = AbstractType::Handle(sig_cls.DeclarationType());
@@ skipping 16 matching lines @@
 
 DEFINE_NATIVE_ENTRY(VariableMirror_type, 2) {
   GET_NON_NULL_NATIVE_ARGUMENT(MirrorReference, ref, arguments->NativeArgAt(0));
   const Field& field = Field::Handle(ref.GetFieldReferent());
   GET_NATIVE_ARGUMENT(AbstractType, instantiator, arguments->NativeArgAt(1));
   const AbstractType& type = AbstractType::Handle(field.type());
   return InstantiateType(type, instantiator);
 }
 
 }  // namespace dart