Redo how Type objects are exposed from DDC.

lib/src/compiler/code_generator.dart

Index: lib/src/compiler/code_generator.dart
diff --git a/lib/src/compiler/code_generator.dart b/lib/src/compiler/code_generator.dart
index 1276c85eaeaeed3e9b6f4a7bbe8d4cff67e002fc..105f4c9088ce453203598669240aa023882edbac 100644
--- a/lib/src/compiler/code_generator.dart
+++ b/lib/src/compiler/code_generator.dart
@@ -116,6 +116,9 @@ class CodeGenerator extends GeneralizingAstVisitor
 
   String _buildRoot;
 
+  /// Whether we are currently generating code for the body of a `JS()` call.
+  bool _isInForeignJS = false;
+
   CodeGenerator(AnalysisContext c, this.options, this._extensionTypes)
       : context = c,
         types = c.typeProvider,
@@ -219,7 +222,6 @@ class CodeGenerator extends GeneralizingAstVisitor
     // Add implicit dart:core dependency so it is first.
     emitLibraryName(dartCoreLibrary);
 
-    //
     // Visit each compilation unit and emit its code.
     //
     // NOTE: declarations are not necessarily emitted in this order.
@@ -2009,7 +2011,19 @@ class CodeGenerator extends GeneralizingAstVisitor
 
     // type literal
     if (element is TypeDefiningElement) {
-      return _emitTypeName(fillDynamicTypeArgs(element.type));
+      var typeName = _emitTypeName(fillDynamicTypeArgs(element.type));
+
+      // If the type is a type literal expression in Dart code, wrap the raw
+      // runtime type in a "Type" instance.
+      if (!_isInForeignJS &&
+          node.parent is! MethodInvocation &&
+          node.parent is! PrefixedIdentifier &&
+          node.parent is! PropertyAccess) {
+        // A type literal expression in use. Wrap the runtime type in a "Type" object.

[Jennifer Messerly, 2016/05/03 20:59:54]

long line.

[Bob Nystrom, 2016/05/03 21:24:32]

Oops. Meant to delete that comment (I moved it outside of the if()). Fixed.

+        typeName = js.call('dart.wrapType(#)', typeName);
+      }
+
+      return typeName;
     }
 
     // library member
@@ -2477,11 +2491,22 @@ class CodeGenerator extends GeneralizingAstVisitor
         source = (code as StringLiteral).stringValue;
       }
 
-      var template = js.parseForeignJS(source);
-      var result = template.instantiate(_visitList(templateArgs));
-      // `throw` is emitted as a statement by `parseForeignJS`.
-      assert(result is JS.Expression || node.parent is ExpressionStatement);
-      return result;
+      // TODO(rnystrom): The JS() calls are almost never nested, and probably
+      // really shouldn't be, but there are at least a couple of calls in the
+      // HTML library where an argument to JS() is itself a JS() call. If those

[Jennifer Messerly, 2016/05/03 20:59:54]

haha, wow. The crazy stuff you find sometimes :)

[Bob Nystrom, 2016/05/03 21:24:32]

Acknowledged.

+      // go away, this can just assert(!_isInForeignJS).
+      var wasInForeignJS = _isInForeignJS;
+      try {

[Jennifer Messerly, 2016/05/03 20:59:54]

nit: try/finally is not needed. We will never try and reuse this visitor
instance if something goes wrong and throws (that means an internal compiler
error). So handling an exception is not required.

[Bob Nystrom, 2016/05/03 21:24:32]

Done.

+        _isInForeignJS = true;
+
+        var template = js.parseForeignJS(source);
+        var result = template.instantiate(_visitList(templateArgs));
+        // `throw` is emitted as a statement by `parseForeignJS`.
+        assert(result is JS.Expression || node.parent is ExpressionStatement);
+        return result;
+      } finally {
+        _isInForeignJS = wasInForeignJS;
+      }
     }
     return null;
   }