Create a NullErrorReporter to use when errors don't need to be recorded.

pkg/analyzer/lib/src/generated/resolver.dart

Index: pkg/analyzer/lib/src/generated/resolver.dart
diff --git a/pkg/analyzer/lib/src/generated/resolver.dart b/pkg/analyzer/lib/src/generated/resolver.dart
index f57ded7a9d4899d800c9615298056c9f16311abb..593c04c5dc5d4dbb1d30876cdf393a52aa1a7f64 100644
--- a/pkg/analyzer/lib/src/generated/resolver.dart
+++ b/pkg/analyzer/lib/src/generated/resolver.dart
@@ -1458,9 +1458,8 @@ class ConstantVerifier extends RecursiveAstVisitor<Object> {
         }
       } else {
         // Note: we throw the errors away because this isn't actually a const.
-        BooleanErrorListener errorListener = new BooleanErrorListener();
-        ErrorReporter subErrorReporter = new ErrorReporter(errorListener, _errorReporter.source);
-        DartObjectImpl result = key.accept(new ConstantVisitor.con1(_typeProvider, subErrorReporter));
+        ErrorReporter nullErrorReporter = new NullErrorReporter(_errorReporter.source);
+        DartObjectImpl result = key.accept(new ConstantVisitor.con1(_typeProvider, nullErrorReporter));
         if (result != null) {
           if (keys.contains(result)) {
             invalidKeys.add(key);
@@ -1635,7 +1634,7 @@ class ConstantVerifier extends RecursiveAstVisitor<Object> {
    */
   DartObjectImpl _validate(Expression expression, ErrorCode errorCode) {
     RecordingErrorListener errorListener = new RecordingErrorListener();
-    ErrorReporter subErrorReporter = new ErrorReporter(errorListener, _errorReporter.source);
+    ErrorReporter subErrorReporter = new ErrorReporterImpl(errorListener, _errorReporter.source);
     DartObjectImpl result = expression.accept(new ConstantVisitor.con1(_typeProvider, subErrorReporter));
     _reportErrors(errorListener.errors, errorCode);
     return result;
@@ -1725,9 +1724,8 @@ class ConstantVerifier extends RecursiveAstVisitor<Object> {
             if (initializer != null) {
               // Ignore any errors produced during validation--if the constant can't be eavluated
               // we'll just report a single error.
-              BooleanErrorListener errorListener = new BooleanErrorListener();
-              ErrorReporter subErrorReporter = new ErrorReporter(errorListener, _errorReporter.source);
-              DartObjectImpl result = initializer.accept(new ConstantVisitor.con1(_typeProvider, subErrorReporter));
+              ErrorReporter nullErrorReporter = new NullErrorReporter(_errorReporter.source);
+              DartObjectImpl result = initializer.accept(new ConstantVisitor.con1(_typeProvider, nullErrorReporter));
               if (result == null) {
                 _errorReporter.reportErrorForNode(CompileTimeErrorCode.CONST_CONSTRUCTOR_WITH_FIELD_INITIALIZED_BY_NON_CONST, errorSite, [variableDeclaration.name.name]);
               }
@@ -1747,7 +1745,7 @@ class ConstantVerifier extends RecursiveAstVisitor<Object> {
    */
   void _validateInitializerExpression(List<ParameterElement> parameterElements, Expression expression) {
     RecordingErrorListener errorListener = new RecordingErrorListener();
-    ErrorReporter subErrorReporter = new ErrorReporter(errorListener, _errorReporter.source);
+    ErrorReporter subErrorReporter = new ErrorReporterImpl(errorListener, _errorReporter.source);
     DartObjectImpl result = expression.accept(new ConstantVisitor_ConstantVerifier_validateInitializerExpression(_typeProvider, subErrorReporter, this, parameterElements));
     _reportErrors(errorListener.errors, CompileTimeErrorCode.NON_CONSTANT_VALUE_IN_INITIALIZER);
     if (result != null) {
@@ -13417,7 +13415,7 @@ class HintGenerator {
           }
         }
       }
-      ErrorReporter definingCompilationUnitErrorReporter = new ErrorReporter(_errorListener, _compilationUnits[0].element.source);
+      ErrorReporter definingCompilationUnitErrorReporter = new ErrorReporterImpl(_errorListener, _compilationUnits[0].element.source);
       _importsVerifier.generateDuplicateImportHints(definingCompilationUnitErrorReporter);
       _importsVerifier.generateUnusedImportHints(definingCompilationUnitErrorReporter);
     } finally {
@@ -13426,7 +13424,7 @@ class HintGenerator {
   }
 
   void _generateForCompilationUnit(CompilationUnit unit, Source source) {
-    ErrorReporter errorReporter = new ErrorReporter(_errorListener, source);
+    ErrorReporter errorReporter = new ErrorReporterImpl(_errorListener, source);
     unit.accept(_importsVerifier);
     // dead code analysis
     unit.accept(new DeadCodeVerifier(errorReporter));