only suggest rethrow inside catch block - fixes #24214

pkg/analysis_server/lib/src/services/completion/keyword_contributor.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.contributor.dart.keyword;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/services/completion/dart_completion_manager.dart';
 import 'package:analyzer/src/generated/ast.dart';
@@ skipping 51 matching lines @@
         Token next = token.next;
         if (next.isSynthetic) {
           next = next.next;
         }
         if (previous.lexeme == ')' && next.lexeme == '{') {
           _addSuggestion2(ASYNC);
         }
       }
     }
     _addStatementKeywords(node);
+    if (_inCatchClause(node)) {
+      _addSuggestion(Keyword.RETHROW, DART_RELEVANCE_KEYWORD - 1);
+    }
   }
 
   @override
   visitClassDeclaration(ClassDeclaration node) {
     // Don't suggest class name
     if (entity == node.name) {
       return;
     }
     if (entity == node.rightBracket) {
       _addClassBodyKeywords();
@@ skipping 356 matching lines @@
       Keyword.IF,
       Keyword.NEW,
       Keyword.RETURN,
       Keyword.SWITCH,
       Keyword.THROW,
       Keyword.TRY,
       Keyword.VAR,
       Keyword.VOID,
       Keyword.WHILE
     ]);
-    _addSuggestion(Keyword.RETHROW, DART_RELEVANCE_KEYWORD - 1);
   }
 
   void _addSuggestion(Keyword keyword,
       [int relevance = DART_RELEVANCE_KEYWORD]) {
     _addSuggestion2(keyword.syntax, relevance: relevance);
   }
 
   void _addSuggestion2(String completion,
       {int offset, int relevance: DART_RELEVANCE_KEYWORD}) {
     if (offset == null) {
@@ skipping 14 matching lines @@
     keywords.forEach((Keyword keyword) {
       _addSuggestion(keyword, relevance);
     });
   }
 
   bool _inAsyncMethodOrFunction(AstNode node) {
     FunctionBody body = node.getAncestor((n) => n is FunctionBody);
     return body != null && body.isAsynchronous;
   }
 
+  bool _inCatchClause(Block node) =>
+      node.getAncestor((p) => p is CatchClause) != null;
+
   bool _inClassMemberBody(AstNode node) {
     while (true) {
       AstNode body = node.getAncestor((n) => n is FunctionBody);
       if (body == null) {
         return false;
       }
       AstNode parent = body.parent;
       if (parent is ConstructorDeclaration || parent is MethodDeclaration) {
         return true;
       }
@@ skipping 10 matching lines @@
 
   bool _inLoop(AstNode node) =>
       _inDoLoop(node) || _inForLoop(node) || _inWhileLoop(node);
 
   bool _inSwitch(AstNode node) =>
       node.getAncestor((p) => p is SwitchStatement) != null;
 
   bool _inWhileLoop(AstNode node) =>
       node.getAncestor((p) => p is WhileStatement) != null;
 }