Issue 3271. Top-level function 'main' should not have parameters

compiler/java/com/google/dart/compiler/resolver/MemberBuilder.java

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file

[Brian Wilkerson, 2012/06/05 14:44:03]

nit: copyright year

 // 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.
 
 package com.google.dart.compiler.resolver;
 
 import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Objects;
 import com.google.dart.compiler.DartCompilerContext;
 import com.google.dart.compiler.ErrorCode;
 import com.google.dart.compiler.ast.ASTVisitor;
 import com.google.dart.compiler.ast.DartBlock;
 import com.google.dart.compiler.ast.DartClass;
 import com.google.dart.compiler.ast.DartExpression;
 import com.google.dart.compiler.ast.DartField;
 import com.google.dart.compiler.ast.DartFieldDefinition;
 import com.google.dart.compiler.ast.DartFunctionTypeAlias;
 import com.google.dart.compiler.ast.DartIdentifier;
@@ skipping 127 matching lines @@
             addMethod(currentHolder, element);
             break;
         }
       } else {
         // This is a top-level element, and an element was already created in
         // TopLevelElementBuilder.
         Elements.addMethod(currentHolder, element);
         assertTopLevel(method);
       }
       if (element != null) {
+        checkTopLevelMainFunction(method);
         checkModifiers(element, method);
         recordElement(method, element);
         recordElement(method.getName(), element);
         ResolutionContext previous = context;
         context = context.extend(element.getName());
         EnclosingElement previousEnclosingElement = enclosingElement;
         enclosingElement = element;
         resolveFunction(method.getFunction(), element);
         enclosingElement = previousEnclosingElement;
         context = previous;
@@ skipping 276 matching lines @@
         } else {
           // Multiple qualifiers (Foo.bar.baz)
           resolutionError(method.getName(),
                           ResolverErrorCode.TOO_MANY_QUALIFIERS_FOR_METHOD);
         }
       }
 
       return ElementKind.NONE;
     }
 
+    /**
+     * Checks that top-level "main()" has no parameters.
+     */
+    private void checkTopLevelMainFunction(DartMethodDefinition method) {
+      if (Objects.equal(method.getName().toSource(), "main")
+          && currentHolder instanceof LibraryElement
+          && !method.getFunction().getParameters().isEmpty()) {
+        resolutionError(method.getName(), ResolverErrorCode.MAIN_FUNCTION_PARAMETERS);
+      }
+    }
+
     private void checkModifiers(MethodElement element, DartMethodDefinition method) {
       Modifiers modifiers = method.getModifiers();
       boolean isNonFactoryConstructor = Elements.isNonFactoryConstructor(element);
       // TODO(ngeoffray): The errors should report the position of the modifier.
       if (isNonFactoryConstructor) {
         if (modifiers.isStatic()) {
           resolutionError(method.getName(), ResolverErrorCode.CONSTRUCTOR_CANNOT_BE_STATIC);
         }
         if (modifiers.isAbstract()) {
           resolutionError(method.getName(), ResolverErrorCode.CONSTRUCTOR_CANNOT_BE_ABSTRACT);
@@ skipping 103 matching lines @@
      */
     private void reportDuplicateDeclaration(ErrorCode errorCode, Element element) {
       String name =
           element instanceof MethodElement
               ? Elements.getRawMethodName((MethodElement) element)
               : element.getName();
       resolutionError(element.getNameLocation(), errorCode, name);
     }
   }
 }