Fix _isDynamicExpression() in DartUnitHighlightsComputer2.

The staticType of an "expression" can be `null` if it is not really
an expression, e.g. an import prefix, or a name of an extension.

[email protected], [email protected]

Change-Id: I9eb328453e77fa51ff0f2d289972ad1274a9a5e6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/114558
Reviewed-by: Phil Quitslund <[email protected]>
Reviewed-by: Brian Wilkerson <[email protected]>

Author: scheglov

pkg/analysis_server/lib/src/computer/computer_highlights2.dart

@@ -3,7 +3,6 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:analyzer/dart/ast/ast.dart';
-import 'package:analyzer/dart/ast/standard_resolution_map.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/dart/element/element.dart';
@@ -425,10 +424,8 @@ class DartUnitHighlightsComputer2 {
   }
 
   static bool _isDynamicExpression(Expression e) {
-    if (e is SimpleIdentifier && e.staticElement is PrefixElement) {
-      return false;
-    }
-    return resolutionMap.staticTypeForExpression(e).isDynamic;
+    var type = e.staticType;
+    return type != null && type.isDynamic;
   }
 }
 

pkg/analysis_server/test/src/computer/highlights2_computer_test.dart

@@ -38,6 +38,18 @@ extension E on String {}
     _check(HighlightRegionType.BUILT_IN, 'on');
   }
 
+  test_methodInvocation_ofExtensionOverride_unresolved() async {
+    createAnalysisOptionsFile(experiments: ['extension-methods']);
+    await _computeHighlights('''
+extension E on int {}
+
+main() {
+  E(0).foo();
+}
+''', hasErrors: true);
+    _check(HighlightRegionType.IDENTIFIER_DEFAULT, 'foo');
+  }
+
   void _check(HighlightRegionType expectedType, String expectedText) {
     for (var region in highlights) {
       if (region.type == expectedType) {
@@ -52,11 +64,20 @@ extension E on String {}
     fail('Expected region of type $expectedType with text "$expectedText"');
   }
 
-  Future<void> _computeHighlights(String content) async {
+  Future<void> _computeHighlights(
+    String content, {
+    bool hasErrors = false,
+  }) async {
     this.content = content;
     newFile(sourcePath, content: content);
     ResolvedUnitResult result = await session.getResolvedUnit(sourcePath);
-    expect(result.errors, hasLength(0));
+
+    if (hasErrors) {
+      expect(result.errors, isNotEmpty);
+    } else {
+      expect(result.errors, isEmpty);
+    }
+
     DartUnitHighlightsComputer2 computer =
         new DartUnitHighlightsComputer2(result.unit);
     highlights = computer.compute();

pkg/analysis_server/test/src/computer/highlights_computer_test.dart

@@ -38,6 +38,18 @@ extension E on String {}
     _check(HighlightRegionType.BUILT_IN, 'on');
   }
 
+  test_methodInvocation_ofExtensionOverride_unresolved() async {
+    createAnalysisOptionsFile(experiments: ['extension-methods']);
+    await _computeHighlights('''
+extension E on int {}
+
+main() {
+  E(0).foo();
+}
+''', hasErrors: true);
+    _check(HighlightRegionType.IDENTIFIER_DEFAULT, 'foo');
+  }
+
   void _check(HighlightRegionType expectedType, String expectedText) {
     for (var region in highlights) {
       if (region.type == expectedType) {
@@ -52,11 +64,20 @@ extension E on String {}
     fail('Expected region of type $expectedType with text "$expectedText"');
   }
 
-  Future<void> _computeHighlights(String content) async {
+  Future<void> _computeHighlights(
+    String content, {
+    bool hasErrors = false,
+  }) async {
     this.content = content;
     newFile(sourcePath, content: content);
     ResolvedUnitResult result = await session.getResolvedUnit(sourcePath);
-    expect(result.errors, hasLength(0));
+
+    if (hasErrors) {
+      expect(result.errors, isNotEmpty);
+    } else {
+      expect(result.errors, isEmpty);
+    }
+
     DartUnitHighlightsComputer computer =
         new DartUnitHighlightsComputer(result.unit);
     highlights = computer.compute();