Improve annotation of type variables in type inference tests.

pkg/analyzer/test/src/task/strong/front_end_inference_test.dart

 // Copyright (c) 2017, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
@@ skipping 78 matching lines @@
   final ConstructorElement currentFactoryConstructor;
 
   _ElementNamer(this.currentFactoryConstructor);
 
   void appendElementName(StringBuffer buffer, Element element) {
     // Synthetic FunctionElement(s) don't have a name or enclosing library.
     if (element.isSynthetic && element is FunctionElement) {
       return;
     }
 
-    LibraryElement library = element.library;
-    if (library == null) {
-      throw new StateError('Unexpected element without library: $element');
+    var enclosing = element.enclosingElement;
+    if (enclosing is CompilationUnitElement) {
+      enclosing = enclosing.enclosingElement;
+    } else if (enclosing is ClassElement &&
+        currentFactoryConstructor != null &&
+        identical(enclosing, currentFactoryConstructor.enclosingElement) &&
+        element is TypeParameterElement) {
+      enclosing = currentFactoryConstructor;
     }
-    String libraryName = library.name;
+    if (enclosing != null) {
+      if (enclosing is LibraryElement &&
+          (enclosing.name == 'dart.core' ||
+              enclosing.name == 'dart.async' ||
+              enclosing.name == 'test')) {
+        // For brevity, omit library name
+      } else {
+        appendElementName(buffer, enclosing);
+        buffer.write('::');
+      }
+    }
 
     String name = element.name ?? '';
-    if (name.endsWith('=') &&
+    if (element is ConstructorElement && name == '') {
+      name = '•';
+    } else if (name.endsWith('=') &&
         element is PropertyAccessorElement &&
         element.isSetter) {
       name = name.substring(0, name.length - 1);
     }
-    if (libraryName != 'dart.core' &&
-        libraryName != 'dart.async' &&
-        libraryName != 'test') {
-      buffer.write('$libraryName::');
-    }
-    var enclosing = element.enclosingElement;
-    if (enclosing is ClassElement) {
-      buffer.write('${enclosing.name}::');
-      if (currentFactoryConstructor != null &&
-          identical(enclosing, currentFactoryConstructor.enclosingElement) &&
-          element is TypeParameterElement) {
-        String factoryConstructorName = currentFactoryConstructor.name;
-        if (factoryConstructorName == '') {
-          factoryConstructorName = '•';
-        }
-        buffer.write('$factoryConstructorName::');
-      }
-    }
-    buffer.write('$name');
+    buffer.write(name);
   }
 }
 
 class _FrontEndInferenceTest extends BaseAnalysisDriverTest {
   Future<String> runTest(String path, String code) async {
     Uri uri = provider.pathContext.toUri(path);
 
     List<int> lineStarts = new LineInfo.fromContent(code).lineStarts;
     fasta.CompilerContext.current.uriToSource[relativizeUri(uri).toString()] =
         new fasta.Source(lineStarts, UTF8.encode(code));
@@ skipping 383 matching lines @@
 
   /// Based on DDC code generator's `_recoverTypeArguments`
   Iterable<DartType> _recoverTypeArguments(FunctionType g, FunctionType f) {
     assert(identical(g.element, f.element));
     assert(g.typeFormals.isNotEmpty && f.typeFormals.isEmpty);
     assert(g.typeFormals.length + g.typeArguments.length ==
         f.typeArguments.length);
     return f.typeArguments.skip(g.typeArguments.length);
   }
 }