Issue 23091. Fix for adding import prefix before string-interpolated identifier.

pkg/analysis_server/lib/src/services/refactoring/rename_import.dart

Index: pkg/analysis_server/lib/src/services/refactoring/rename_import.dart
diff --git a/pkg/analysis_server/lib/src/services/refactoring/rename_import.dart b/pkg/analysis_server/lib/src/services/refactoring/rename_import.dart
index e58b535de27dc25b613951afb7842d6028ef3131..e2f009dcd1bec4b88e90acde8a18ad4443a2358b 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/rename_import.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/rename_import.dart
@@ -14,6 +14,7 @@ import 'package:analysis_server/src/services/refactoring/refactoring.dart';
 import 'package:analysis_server/src/services/refactoring/refactoring_internal.dart';
 import 'package:analysis_server/src/services/refactoring/rename.dart';
 import 'package:analysis_server/src/services/search/search_engine.dart';
+import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/element.dart';
 import 'package:analyzer/src/generated/source.dart';
 
@@ -76,10 +77,34 @@ class RenameImportRefactoringImpl extends RenameRefactoringImpl {
     List<SourceReference> references = getSourceReferences(matches);
     for (SourceReference reference in references) {
       if (newName.isEmpty) {
-        reference.addEdit(change, newName);
+        reference.addEdit(change, '');
       } else {
-        reference.addEdit(change, "${newName}.");
+        SimpleIdentifier interpolationIdentifier =
+            _getInterpolationIdentifier(reference);
+        if (interpolationIdentifier != null) {
+          doSourceChange_addElementEdit(change, reference.element,
+              new SourceEdit(interpolationIdentifier.offset,
+                  interpolationIdentifier.length,
+                  '{$newName.${interpolationIdentifier.name}}'));
+        } else {
+          reference.addEdit(change, '$newName.');
+        }
       }
     }
   }
+
+  /**
+   * If the given [reference] is before an [SimpleIdentifier] in an
+   * [InterpolationElement], return it. Otherwise return `null`.
+   */
+  SimpleIdentifier _getInterpolationIdentifier(SourceReference reference) {
+    Source source = reference.element.source;
+    CompilationUnit unit = context.parseCompilationUnit(source);
+    NodeLocator nodeLocator = new NodeLocator.con1(reference.range.offset);
+    AstNode node = nodeLocator.searchWithin(unit);
+    if (node is SimpleIdentifier && node.parent is InterpolationExpression) {

[Paul Berry, 2015/04/03 21:25:27]

I don't think this is quite right.  This if-test will pass both for the case of
renaming $x and for renaming ${x}.  Which means that ${x} will get incorrectly
renamed to ${{prefix.x}}.

[scheglov, 2015/04/03 21:33:28]

Fixed.

+      return node;
+    }
+    return null;
+  }
 }