Print the location of duplicated elements.

dart/sdk/lib/_internal/compiler/implementation/resolution/members.dart

Index: dart/sdk/lib/_internal/compiler/implementation/resolution/members.dart
diff --git a/dart/sdk/lib/_internal/compiler/implementation/resolution/members.dart b/dart/sdk/lib/_internal/compiler/implementation/resolution/members.dart
index 9504271cb652c2ed082e0c52d1e94bb317b7bf18..1b04830a70facfd47d674c5d399e9d900e381176 100644
--- a/dart/sdk/lib/_internal/compiler/implementation/resolution/members.dart
+++ b/dart/sdk/lib/_internal/compiler/implementation/resolution/members.dart
@@ -1475,6 +1475,25 @@ class TypeResolver {
       AmbiguousElement ambiguous = element;
       type = reportFailureAndCreateType(
           ambiguous.messageKind, ambiguous.messageArguments);
+      if (ambiguous.existingElement == ambiguous.newElement) {
+        compiler.reportMessage(
+            compiler.spanFromSpannable(ambiguous.existingElement),
+            MessageKind.GENERIC.error(
+                {'text': 'Giladism: you cannot refer to the same element '

[ahe, 2013/04/17 14:56:25]

Perhaps Gilad can help us come up with a better error message ;-)

+                      'through different imports.'}),
+            Diagnostic.INFO);
+      } else {
+        compiler.reportMessage(
+            compiler.spanFromSpannable(ambiguous.existingElement),
+            MessageKind.GENERIC.error(
+                {'text': 'Note: this is the location of the first element.'}),
+            Diagnostic.INFO);
+        compiler.reportMessage(
+            compiler.spanFromSpannable(ambiguous.newElement),
+            MessageKind.GENERIC.error(
+                {'text': 'Note: this is the location of the second element.'}),
+            Diagnostic.INFO);
+      }
     } else if (!element.impliesType()) {
       type = reportFailureAndCreateType(
           MessageKind.NOT_A_TYPE, {'node': node.typeName});
@@ -1655,6 +1674,26 @@ class ResolverVisitor extends CommonResolverVisitor<Element> {
         AmbiguousElement ambiguous = result;
         compiler.reportErrorCode(
             node, ambiguous.messageKind, ambiguous.messageArguments);
+        if (ambiguous.existingElement == ambiguous.newElement) {
+          compiler.reportMessage(
+              compiler.spanFromSpannable(ambiguous.existingElement),
+              MessageKind.GENERIC.error(
+                  {'text': 'Giladism: you cannot refer to the same element '
+                        'through different imports.'}),
+              Diagnostic.INFO);
+        } else {
+          compiler.reportMessage(
+              compiler.spanFromSpannable(ambiguous.existingElement),
+              MessageKind.GENERIC.error(
+                  {'text': 'Note: this is the location of the first element.'}),
+              Diagnostic.INFO);
+          compiler.reportMessage(
+              compiler.spanFromSpannable(ambiguous.newElement),
+              MessageKind.GENERIC.error(
+                  {'text':
+                    'Note: this is the location of the second element.'}),
+              Diagnostic.INFO);
+        }
         return new ErroneousElementX(ambiguous.messageKind,
                                      ambiguous.messageArguments,
                                      name, enclosingElement);