Don't suggest generative constructors of abstract classes.

So, we don't suggest EdgeInsetsGeometry for 'padding: ', even though
it is the type of the parameters. But we still suggest its subclasses
EdgeInsets and EdgeInsetsDirectional.

[email protected], [email protected]

Bug: flutter/flutter-intellij#998
Change-Id: If2d7ba550ec76e4f66cb81e1346466b5f1a30464
Reviewed-on: https://dart-review.googlesource.com/42888
Reviewed-by: Brian Wilkerson <[email protected]>

Author: scheglov

pkg/analysis_server/lib/src/services/completion/dart/local_constructor_contributor.dart

@@ -106,7 +106,6 @@ class _Visitor extends LocalDeclarationVisitor {
   void _addSuggestion(
       ClassDeclaration classDecl, ConstructorDeclaration constructorDecl) {
     String completion = classDecl.name.name;
-    SimpleIdentifier elemId;
 
     ClassElement classElement =
         resolutionMap.elementDeclaredByClassDeclaration(classDecl);
@@ -116,29 +115,30 @@ class _Visitor extends LocalDeclarationVisitor {
       return;
     }
 
-    // Build a suggestion for explicitly declared constructor
     if (constructorDecl != null) {
-      elemId = constructorDecl.name;
-      ConstructorElement elem = constructorDecl.element;
-      if (elemId != null) {
-        String name = elemId.name;
-        if (name != null && name.length > 0) {
-          completion = '$completion.$name';
-        }
+      // Build a suggestion for explicitly declared constructor
+      ConstructorElement element = constructorDecl.element;
+      if (element == null) {
+        return;
       }
-      if (elem != null) {
-        CompletionSuggestion suggestion = createSuggestion(elem,
-            completion: completion, relevance: relevance);
-        if (suggestion != null) {
-          suggestions.add(suggestion);
-        }
+      if (classElement.isAbstract && !element.isFactory) {
+        return;
+      }
+
+      String name = constructorDecl.name?.name;
+      if (name != null && name.length > 0) {
+        completion = '$completion.$name';
       }
-    }
 
-    // Build a suggestion for an implicit constructor
-    else {
+      CompletionSuggestion suggestion = createSuggestion(element,
+          completion: completion, relevance: relevance);
+      if (suggestion != null) {
+        suggestions.add(suggestion);
+      }
+    } else if (!classElement.isAbstract) {
+      // Build a suggestion for an implicit constructor
       protocol.Element element = createLocalElement(
-          request.source, protocol.ElementKind.CONSTRUCTOR, elemId,
+          request.source, protocol.ElementKind.CONSTRUCTOR, null,
           parameters: '()');
       element.returnType = classDecl.name.name;
       CompletionSuggestion suggestion = new CompletionSuggestion(

pkg/analysis_server/lib/src/services/completion/dart/local_library_contributor.dart

@@ -147,19 +147,24 @@ class LibraryElementSuggestionBuilder extends GeneralizingElementVisitor
   void _addConstructorSuggestions(ClassElement classElem, int relevance) {
     String className = classElem.name;
     for (ConstructorElement constructor in classElem.constructors) {
-      if (!constructor.isPrivate) {
-        CompletionSuggestion suggestion =
-            createSuggestion(constructor, relevance: relevance);
-        if (suggestion != null) {
-          String name = suggestion.completion;
-          name = name.length > 0 ? '$className.$name' : className;
-          if (prefix != null && prefix.length > 0) {
-            name = '$prefix.$name';
-          }
-          suggestion.completion = name;
-          suggestion.selectionOffset = suggestion.completion.length;
-          suggestions.add(suggestion);
+      if (constructor.isPrivate) {
+        continue;
+      }
+      if (classElem.isAbstract && !constructor.isFactory) {
+        continue;
+      }
+
+      CompletionSuggestion suggestion =
+          createSuggestion(constructor, relevance: relevance);
+      if (suggestion != null) {
+        String name = suggestion.completion;
+        name = name.length > 0 ? '$className.$name' : className;
+        if (prefix != null && prefix.length > 0) {
+          name = '$prefix.$name';
         }
+        suggestion.completion = name;
+        suggestion.selectionOffset = suggestion.completion.length;
+        suggestions.add(suggestion);
       }
     }
   }

pkg/analysis_server/test/services/completion/dart/imported_reference_contributor_test.dart

@@ -2486,6 +2486,44 @@ main() {new ^ String x = "hello";}''');
     assertNotSuggested('math');
   }
 
+  test_InstanceCreationExpression_abstractClass() async {
+    addSource('/a.dart', '''
+abstract class A {
+  A();
+  A.generative();
+  factory A.factory() => null;
+}
+''');
+    addTestSource('''
+import 'a.dart';
+
+main() {
+  new ^;
+}
+''');
+    await computeSuggestions();
+
+    assertNotSuggested('A');
+    assertNotSuggested('A.generative');
+    assertSuggestConstructor('A.factory');
+  }
+
+  test_InstanceCreationExpression_abstractClass_implicitConstructor() async {
+    addSource('/a.dart', '''
+abstract class A {}
+''');
+    addTestSource('''
+import 'a.dart';
+
+main() {
+  new ^;
+}
+''');
+    await computeSuggestions();
+
+    assertNotSuggested('A');
+  }
+
   test_InstanceCreationExpression_imported() async {
     // SimpleIdentifier  TypeName  ConstructorName  InstanceCreationExpression
     addSource('/testA.dart', '''

pkg/analysis_server/test/services/completion/dart/local_constructor_contributor_test.dart

@@ -2289,6 +2289,36 @@ main() {new ^ String x = "hello";}''');
     expect(suggestion.hasNamedParameters, true);
   }
 
+  test_InstanceCreationExpression_abstractClass() async {
+    addTestSource('''
+abstract class A {
+  A();
+  A.generative();
+  factory A.factory() => null;
+}
+
+main() {
+  new ^;
+}''');
+    await computeSuggestions();
+
+    assertNotSuggested('A');
+    assertNotSuggested('A.generative');
+    assertSuggestConstructor('A.factory');
+  }
+
+  test_InstanceCreationExpression_abstractClass_implicitConstructor() async {
+    addTestSource('''
+abstract class A {}
+
+main() {
+  new ^;
+}''');
+    await computeSuggestions();
+
+    assertNotSuggested('A');
+  }
+
   test_InstanceCreationExpression_assignment_expression_filter() async {
     addTestSource('''
 class A {} class B extends A {} class C implements A {} class D {}