Disable completion of formal parameter names as *types*.

pkg/analysis_server/lib/src/services/completion/optype.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.
 
 library services.completion.dart.optype;
 
 import 'package:analysis_server/src/provisional/completion/dart/completion_target.dart';
 import 'package:analyzer/src/generated/ast.dart';
 import 'package:analyzer/src/generated/scanner.dart';
 
@@ skipping 307 matching lines @@
       }
     }
     if (identical(entity, node.iterable)) {
       optype.includeReturnValueSuggestions = true;
       optype.includeTypeNameSuggestions = true;
     }
   }
 
   @override
   void visitFormalParameterList(FormalParameterList node) {
-    optype.includeTypeNameSuggestions = true;
+    dynamic entity = this.entity;
+    if (entity is Token && entity.previous != null) {
+      TokenType type = entity.previous.type;
+      if (type == TokenType.OPEN_PAREN || type == TokenType.COMMA) {
+        optype.includeTypeNameSuggestions = true;
+      }
+    }
+    // Handle default normal parameter just as a normal parameter.
+    if (entity is DefaultFormalParameter) {
+      entity = entity.parameter;
+    }
+    // "(^ this.field)"
+    if (entity is FieldFormalParameter) {
+      if (offset < entity.thisKeyword.offset) {
+        optype.includeTypeNameSuggestions = true;
+      }
+    }
+    // "(Type name)"
+    if (entity is SimpleFormalParameter) {
+      // "(Type^)" is parsed as a parameter with the _name_ "Type".
+      if (entity.type == null) {
+        optype.includeTypeNameSuggestions = true;
+      }
+      // If inside of "Type" in "(Type^ name)", then include types.
+      if (entity.type != null &&
+          entity.type.offset <= offset &&
+          offset <= entity.type.end) {
+        optype.includeTypeNameSuggestions = true;
+      }
+    }
   }
 
   @override
   void visitForStatement(ForStatement node) {
     optype.includeReturnValueSuggestions = true;
     optype.includeTypeNameSuggestions = true;
     optype.includeVoidReturnSuggestions = true;
     // TODO (danrubel) void return suggestions only belong after
     // the 2nd semicolon.  Return value suggestions only belong after the
     // e1st or second semicolon.
@@ skipping 114 matching lines @@
     }
   }
 
   @override
   void visitNode(AstNode node) {
     // no suggestion by default
   }
 
   @override
   void visitNormalFormalParameter(NormalFormalParameter node) {
-    optype.includeReturnValueSuggestions = true;
-    optype.includeTypeNameSuggestions = true;
+    if (node.identifier != entity) {
+      optype.includeReturnValueSuggestions = true;
+      optype.includeTypeNameSuggestions = true;
+    }
   }
 
   void visitParenthesizedExpression(ParenthesizedExpression node) {
     if (identical(entity, node.expression)) {
       optype.includeReturnValueSuggestions = true;
       optype.includeTypeNameSuggestions = true;
     }
   }
 
   @override
@@ skipping 166 matching lines @@
   void visitVariableDeclarationStatement(VariableDeclarationStatement node) {}
 
   @override
   void visitWhileStatement(WhileStatement node) {
     if (identical(entity, node.condition)) {
       optype.includeReturnValueSuggestions = true;
       optype.includeTypeNameSuggestions = true;
     }
   }
 }