Use DartEditBuilder to write types and remove dead code

pkg/analysis_server/lib/src/services/correction/assist_internal.dart

 // Copyright (c) 2014, 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:collection';
 
 import 'package:analysis_server/plugin/edit/assist/assist_core.dart';
 import 'package:analysis_server/plugin/edit/assist/assist_dart.dart';
 import 'package:analysis_server/src/services/correction/assist.dart';
@@ skipping 203 matching lines @@
     if (declaredIdentifier.type != null) {
       _coverageMarker();
       return;
     }
     DartType type = declaredIdentifier.identifier.bestType;
     if (type is! InterfaceType && type is! FunctionType) {
       _coverageMarker();
       return;
     }
     _configureTargetLocation(node);
-    Set<Source> librariesToImport = new Set<Source>();
-    String typeSource = utils.getTypeSource(type, librariesToImport);
-    if (typeSource == null) {
-      // The type source might be null if the type is private.
-      _coverageMarker();
-      return;
-    }
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
+    bool validChange = true;
     await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
       Token keyword = declaredIdentifier.keyword;
       if (keyword.keyword == Keyword.VAR) {
-        builder.addSimpleReplacement(range.token(keyword), typeSource);
+        builder.addReplacement(range.token(keyword), (DartEditBuilder builder) {
+          validChange = builder.writeType(type);
+        });
       } else {
-        builder.addSimpleInsertion(
-            declaredIdentifier.identifier.offset, '$typeSource ');
+        builder.addInsertion(declaredIdentifier.identifier.offset,
+            (DartEditBuilder builder) {
+          validChange = builder.writeType(type);
+          builder.write(' ');
+        });
       }
-      builder.importLibraries(librariesToImport);
     });
-    _addAssistFromBuilder(changeBuilder, DartAssistKind.ADD_TYPE_ANNOTATION);
+    if (validChange) {
+      _addAssistFromBuilder(changeBuilder, DartAssistKind.ADD_TYPE_ANNOTATION);
+    }
   }
 
   Future<Null> _addProposal_addTypeAnnotation_SimpleFormalParameter() async {
     AstNode node = this.node;
     // should be the name of a simple parameter
     if (node is! SimpleIdentifier || node.parent is! SimpleFormalParameter) {
       _coverageMarker();
       return;
     }
     SimpleIdentifier name = node;
     SimpleFormalParameter parameter = node.parent;
     // the parameter should not have a type
     if (parameter.type != null) {
       _coverageMarker();
       return;
     }
     // prepare the type
     DartType type = parameter.element.type;
     // TODO(scheglov) If the parameter is in a method declaration, and if the
     // method overrides a method that has a type for the corresponding
     // parameter, it would be nice to copy down the type from the overridden
     // method.
     if (type is! InterfaceType) {
       _coverageMarker();
       return;
     }
     // prepare type source
     _configureTargetLocation(node);
-    Set<Source> librariesToImport = new Set<Source>();
-    String typeSource = utils.getTypeSource(type, librariesToImport);
-    // type source might be null, if the type is private
-    if (typeSource == null) {
-      _coverageMarker();
-      return;
-    }
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
+    bool validChange = true;
     await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
-      builder.addSimpleInsertion(name.offset, '$typeSource ');
-      builder.importLibraries(librariesToImport);
+      builder.addInsertion(name.offset, (DartEditBuilder builder) {
+        validChange = builder.writeType(type);
+        builder.write(' ');
+      });
     });
-    _addAssistFromBuilder(changeBuilder, DartAssistKind.ADD_TYPE_ANNOTATION);
+    if (validChange) {
+      _addAssistFromBuilder(changeBuilder, DartAssistKind.ADD_TYPE_ANNOTATION);
+    }
   }
 
   Future<Null> _addProposal_addTypeAnnotation_VariableDeclaration() async {
     AstNode node = this.node;
     // prepare VariableDeclarationList
     VariableDeclarationList declarationList =
         node.getAncestor((node) => node is VariableDeclarationList);
     if (declarationList == null) {
       _coverageMarker();
       return;
@@ skipping 22 matching lines @@
       return;
     }
     DartType type = initializer.bestType;
     // prepare type source
     if ((type is! InterfaceType || type.isDartCoreNull) &&
         type is! FunctionType) {
       _coverageMarker();
       return;
     }
     _configureTargetLocation(node);
-    Set<Source> librariesToImport = new Set<Source>();
-    String typeSource = utils.getTypeSource(type, librariesToImport);
-    // type source might be null, if the type is private
-    if (typeSource == null) {
-      _coverageMarker();
-      return;
-    }
 
     DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
-    if (unitLibraryFile == file) {
-      // TODO(brianwilkerson) Make ChangeBuilder merge multiple edits to the
-      // same file so that only the else block is necessary.
-      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
-        Token keyword = declarationList.keyword;
-        if (keyword?.keyword == Keyword.VAR) {
-          builder.addSimpleReplacement(range.token(keyword), typeSource);
-        } else {
-          builder.addSimpleInsertion(variable.offset, '$typeSource ');
-        }
-        builder.importLibraries(librariesToImport);
-      });
-    } else {
-      await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
-        Token keyword = declarationList.keyword;
-        if (keyword?.keyword == Keyword.VAR) {
-          builder.addSimpleReplacement(range.token(keyword), typeSource);
-        } else {
-          builder.addSimpleInsertion(variable.offset, '$typeSource ');
-        }
-      });
-      await changeBuilder.addFileEdit(unitLibraryFile,
-          (DartFileEditBuilder builder) {
-        builder.importLibraries(librariesToImport);
-      });
+    bool validChange = true;
+    await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
+      Token keyword = declarationList.keyword;
+      if (keyword?.keyword == Keyword.VAR) {
+        builder.addReplacement(range.token(keyword), (DartEditBuilder builder) {
+          validChange = builder.writeType(type);
+        });
+      } else {
+        builder.addInsertion(variable.offset, (DartEditBuilder builder) {
+          validChange = builder.writeType(type);
+          builder.write(' ');
+        });
+      }
+    });
+    if (validChange) {
+      _addAssistFromBuilder(changeBuilder, DartAssistKind.ADD_TYPE_ANNOTATION);
     }
-    _addAssistFromBuilder(changeBuilder, DartAssistKind.ADD_TYPE_ANNOTATION);
   }
 
   Future<Null> _addProposal_assignToLocalVariable() async {
     // prepare enclosing ExpressionStatement
     ExpressionStatement expressionStatement;
     for (AstNode node = this.node; node != null; node = node.parent) {
       if (node is ExpressionStatement) {
         expressionStatement = node;
         break;
       }
@@ skipping 710 matching lines @@
         node.parent is FieldFormalParameter &&
         node.parent.parent is FormalParameterList &&
         node.parent.parent.parent is ConstructorDeclaration) {
       ConstructorDeclaration constructor = node.parent.parent.parent;
       FormalParameterList parameterList = node.parent.parent;
       FieldFormalParameter parameter = node.parent;
       ParameterElement parameterElement = parameter.element;
       String name = (node as SimpleIdentifier).name;
       // prepare type
       DartType type = parameterElement.type;
-      Set<Source> librariesToImport = new Set<Source>();
-      String typeCode = utils.getTypeSource(type, librariesToImport);
 
       DartChangeBuilder changeBuilder = new DartChangeBuilder(driver);
       await changeBuilder.addFileEdit(file, (DartFileEditBuilder builder) {
         // replace parameter
         if (type.isDynamic) {
           builder.addSimpleReplacement(range.node(parameter), name);
         } else {
-          builder.addSimpleReplacement(
-              range.node(parameter), '$typeCode $name');
+          builder.addReplacement(range.node(parameter),
+              (DartEditBuilder builder) {
+            builder.writeType(type);
+            builder.write(' ');
+            builder.write(name);
+          });
         }
         // add field initializer
         List<ConstructorInitializer> initializers = constructor.initializers;
         if (initializers.isEmpty) {
           builder.addSimpleInsertion(parameterList.end, ' : $name = $name');
         } else {
           builder.addSimpleInsertion(initializers.last.end, ', $name = $name');
         }
       });
       _addAssistFromBuilder(
@@ skipping 1463 matching lines @@
 class _SimpleIdentifierRecursiveAstVisitor extends RecursiveAstVisitor {
   final _SimpleIdentifierVisitor visitor;
 
   _SimpleIdentifierRecursiveAstVisitor(this.visitor);
 
   @override
   visitSimpleIdentifier(SimpleIdentifier node) {
     visitor(node);
   }
 }