fix #27631, get/set methods no longer shadow index operator

R=rnystrom@google.com

Review URL: https://codereview.chromium.org/2435163002 .

pkg/dev_compiler/lib/src/compiler/code_generator.dart

@@ -4481,7 +4481,10 @@ class CodeGenerator extends GeneralizingAstVisitor
           context: expr);
     }
 
-    return _emitSend(expr, op.lexeme[0], []);
+    var operatorName = op.lexeme;
+    // Use the name from the Dart spec.
+    if (operatorName == '-') operatorName = 'unary-';
+    return _emitSend(expr, operatorName, []);
   }
 
   // Cascades can contain [IndexExpression], [MethodInvocation] and
@@ -4714,7 +4717,7 @@ class CodeGenerator extends GeneralizingAstVisitor
   JS.Expression _emitSend(
       Expression target, String name, List<Expression> args) {
     var type = getStaticType(target);
-    var memberName = _emitMemberName(name, unary: args.isEmpty, type: type);
+    var memberName = _emitMemberName(name, type: type);
     if (isDynamicInvoke(target)) {
       if (_inWhitelistCode(target)) {
         var vars = <JS.MetaLetVariable, JS.Expression>{};
@@ -5226,7 +5229,6 @@ class CodeGenerator extends GeneralizingAstVisitor
     }
     return _emitMemberName(name,
         type: (e.enclosingElement as ClassElement).type,
-        unary: e.parameters.isEmpty,
         isStatic: e.isStatic,
         useExtension: useExtension);
   }
@@ -5266,17 +5268,13 @@ class CodeGenerator extends GeneralizingAstVisitor
   /// This follows the same pattern as ECMAScript 6 Map:
   /// <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map>
   ///
-  /// Unary minus looks like: `x['unary-']()`. Note that [unary] must be passed
-  /// for this transformation to happen, otherwise binary minus is assumed.
+  /// Unary minus looks like: `x._negate()`.
   ///
   /// Equality is a bit special, it is generated via the Dart `equals` runtime
   /// helper, that checks for null. The user defined method is called '=='.
   ///
   JS.Expression _emitMemberName(String name,
-      {DartType type,
-      bool unary: false,
-      bool isStatic: false,
-      bool useExtension}) {
+      {DartType type, bool isStatic: false, bool useExtension}) {
     // Static members skip the rename steps.
     if (isStatic) return _propertyName(name);
 
@@ -5284,16 +5282,22 @@ class CodeGenerator extends GeneralizingAstVisitor
       return _emitPrivateNameSymbol(currentLibrary, name);
     }
 
-    if (name == '[]') {
-      name = 'get';
-    } else if (name == '[]=') {
-      name = 'set';
-    } else if (name == '-' && unary) {
-      name = 'unary-';
-    } else if (name == 'constructor' || name == 'prototype') {
-      // This uses an illegal (in Dart) character for a member, avoiding the
-      // conflict. We could use practically any character for this.
-      name = '+$name';
+    // When generating synthetic names, we use _ as the prefix, since Dart names
+    // won't have this (eliminated above), nor will static names reach here.
+    switch (name) {
+      case '[]':
+        name = '_get';
+        break;
+      case '[]=':
+        name = '_set';
+        break;
+      case 'unary-':
+        name = '_negate';
+        break;
+      case 'constructor':
+      case 'prototype':
+        name = '_$name';
+        break;
     }
 
     var result = _propertyName(name);

pkg/dev_compiler/test/codegen_expected/BenchmarkBase.js

@@ -16,7 +16,7 @@ define(['dart_sdk'], function(dart_sdk) {
         dart.throw(dart.str`Lists have different lengths: ${expected[dartx.length]} vs ${actual[dartx.length]}`);
       }
       for (let i = 0; i < dart.notNull(actual[dartx.length]); i++) {
-        BenchmarkBase$.Expect.equals(expected[dartx.get](i), actual[dartx.get](i));
+        BenchmarkBase$.Expect.equals(expected[dartx._get](i), actual[dartx._get](i));
       }
     }
     fail(message) {

pkg/dev_compiler/tool/input_sdk/private/ddc_runtime/operations.dart

@@ -312,10 +312,10 @@ dsend(obj, method, @rest args) => _callMethod(obj, method, null, args, method);
 dgsend(obj, typeArgs, method, @rest args) =>
     _callMethod(obj, method, typeArgs, args, method);
 
-dindex(obj, index) => _callMethod(obj, 'get', null, JS('', '[#]', index), '[]');
+dindex(obj, index) => _callMethod(obj, '_get', null, JS('', '[#]', index), '[]');
 
 dsetindex(obj, index, value) =>
-    _callMethod(obj, 'set', null, JS('', '[#, #]', index, value), '[]=');
+    _callMethod(obj, '_set', null, JS('', '[#, #]', index, value), '[]=');
 
 /// TODO(leafp): This duplicates code in types.dart.
 /// I haven't found a way to factor it out that makes the
@@ -535,11 +535,11 @@ map(values, [K, V]) => JS(
     for (let i = 0, end = $values.length - 1; i < end; i += 2) {
       let key = $values[i];
       let value = $values[i + 1];
-      map.set(key, value);
+      map._set(key, value);
     }
   } else if (typeof $values === 'object') {
     for (let key of $getOwnPropertyNames($values)) {
-      map.set(key, $values[key]);
+      map._set(key, $values[key]);
     }
   }
   return map;