Implement invoking methods with optional arguments.

dart/sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart

 // Copyright (c) 2012, 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.
 
 part of js_backend;
 
 /// Enables debugging of fast/slow objects using V8-specific primitives.
 const DEBUG_FAST_OBJECTS = false;
 
 /**
@@ skipping 1116 matching lines @@
     // (2) foo$3$c(a, b, c) => foo$4$c$d(a, b, c, null);
     // (3) foo$3$d(a, b, d) => foo$4$c$d(a, b, null, d);
     // (4) No stub generated, call is direct.
     // (5) No stub generated, call is direct.
 
     // Keep a cache of which stubs have already been generated, to
     // avoid duplicates. Note that even if selectors are
     // canonicalized, we would still need this cache: a typed selector
     // on A and a typed selector on B could yield the same stub.
     Set<String> generatedStubNames = new Set<String>();
-    if (compiler.enabledFunctionApply
-        && member.name == namer.closureInvocationSelectorName) {
+    bool isClosureInvocation =
+        member.name == namer.closureInvocationSelectorName;
+    if (backend.isNeededForReflection(member) ||
+        (compiler.enabledFunctionApply && isClosureInvocation)) {
       // If [Function.apply] is called, we pessimistically compile all
       // possible stubs for this closure.
       FunctionSignature signature = member.computeSignature(compiler);
       Set<Selector> selectors = signature.optionalParametersAreNamed
           ? computeSeenNamedSelectors(member)
           : computeOptionalSelectors(signature, member);
       for (Selector selector in selectors) {
         addParameterStub(member, selector, defineStub, generatedStubNames);
       }
-      if (signature.optionalParametersAreNamed) {
+      if (signature.optionalParametersAreNamed && isClosureInvocation) {
         addCatchAllParameterStub(member, signature, defineStub);
       }
     } else {
       Set<Selector> selectors = compiler.codegenWorld.invokedNames[member.name];
       if (selectors == null) return;
       for (Selector selector in selectors) {
         if (!selector.applies(member, compiler)) continue;
         addParameterStub(member, selector, defineStub, generatedStubNames);
       }
     }
   }
 
   Set<Selector> computeSeenNamedSelectors(FunctionElement element) {
     Set<Selector> selectors = compiler.codegenWorld.invokedNames[element.name];
-    if (selectors == null) return null;
     Set<Selector> result = new Set<Selector>();
+    if (selectors == null) return result;
     for (Selector selector in selectors) {
       if (!selector.applies(element, compiler)) continue;
       result.add(selector);
     }
     return result;
   }
 
   void addCatchAllParameterStub(FunctionElement member,
                                 FunctionSignature signature,
                                 DefineStubFunction defineStub) {
@@ skipping 179 matching lines @@
           var names = [];
           for (Element e in signature.optionalParameters) {
             names.add(e.name);
           }
           Selector selector = new Selector.call(
               function.name,
               function.getLibrary(),
               requiredParameterCount,
               names);
           namedArguments = namedParametersAsReflectionNames(selector);
+        } else {
+          // Named parameters are handled differently by mirrors.  For unnamed
+          // parameters, they are actually required if invoked
+          // reflectively. Also, if you have a method c(x) and c([x]) they both
+          // get the same mangled name, so they must have the same reflection
+          // name.
+          requiredParameterCount += optionalParameterCount;
+          optionalParameterCount = 0;
         }
       }
       String suffix =
+          // TODO(ahe): We probably don't need optionalParameterCount in the
+          // reflection name.
           '$name:$requiredParameterCount:$optionalParameterCount'
           '$namedArguments';
       return (isConstructor) ? 'new $suffix' : suffix;
     }
     Element element = elementOrSelector;
     if (element.isGenerativeConstructorBody()) {
       return null;
     } else if (element.isClass()) {
       ClassElement cls = element;
       if (cls.isUnnamedMixinApplication) return null;
@@ skipping 3034 matching lines @@
 
 const String HOOKS_API_USAGE = """
 // The code supports the following hooks:
 // dartPrint(message)   - if this function is defined it is called
 //                        instead of the Dart [print] method.
 // dartMainRunner(main) - if this function is defined, the Dart [main]
 //                        method will not be invoked directly.
 //                        Instead, a closure that will invoke [main] is
 //                        passed to [dartMainRunner].
 """;