Report CompileTimeErrorCode.DUPLICATE_PART when not only URI, but even Source is the same.

pkg/analyzer/lib/src/error/codes.dart

Index: pkg/analyzer/lib/src/error/codes.dart
diff --git a/pkg/analyzer/lib/src/error/codes.dart b/pkg/analyzer/lib/src/error/codes.dart
index 7d9eec5a84b97e3da242c27e3ac0e2a77deb78a9..2fb363c1ae40d0e1c5066e24efc6a3de2189bbd1 100644
--- a/pkg/analyzer/lib/src/error/codes.dart
+++ b/pkg/analyzer/lib/src/error/codes.dart
@@ -754,13 +754,9 @@ class CompileTimeErrorCode extends ErrorCode {
   /**
    * 18.3 Parts: It's a compile-time error if the same library contains two part
    * directives with the same URI.
-   *
-   * Parameters:
-   * 0: the URI of the duplicate part
    */
-  static const CompileTimeErrorCode DUPLICATE_PART = const CompileTimeErrorCode(
-      'DUPLICATE_PART',
-      "The library already contains a part with the uri '{0}'.");
+  static const CompileTimeErrorCode DUPLICATE_PART =
+      const CompileTimeErrorCode('DUPLICATE_PART', 'Duplicate part');

[Brian Wilkerson, 2016/10/06 22:14:11]

I think the old message was better. I think it would be fine if the URI we use
for the message was the resolved URI rather than the string literal from the
directive.

 
   /**
    * 7. Classes: It is a compile-time error if a class has an instance member