Add support for the new function-type syntax.

pkg/compiler/lib/src/resolution/signatures.dart

Index: pkg/compiler/lib/src/resolution/signatures.dart
diff --git a/pkg/compiler/lib/src/resolution/signatures.dart b/pkg/compiler/lib/src/resolution/signatures.dart
index 0dd1363ba46d8a364c3d8b46da3346f74522ad2b..abe17506bc606a9e815c218f6878e5a5fe53f345 100644
--- a/pkg/compiler/lib/src/resolution/signatures.dart
+++ b/pkg/compiler/lib/src/resolution/signatures.dart
@@ -94,7 +94,9 @@ class SignatureResolver extends MappingVisitor<FormalElementX> {
       reporter.internalError(node, 'function type parameters not supported');
     }
     currentDefinitions = node;
-    FormalElementX element = definition.accept(this);
+    FormalElementX element = definition == new NoIdentifier()

[Siggi Cherem (dart-lang), 2016/12/29 22:46:57]

nit: this is more of a readability nit, than anything else. I understand that
the `new NoIdentifier` is returning a singleton instance, but seeing the `new`
here does make you think twice about what this code is doing.

Other options:
  - definition == NoIdentifier.singleton
  - definition.isNoIdentifier // or .isIdentifierPlaceholder
  - definition == null ?

[floitsch, 2016/12/30 14:55:47]

changed to NoIdentifier.singleton
done.

+        ? createUnnamedParameter()  // This happens in function types.
+        : definition.accept(this);
     if (currentDefinitions.metadata != null) {
       element.metadataInternal =
           resolution.resolver.resolveMetadata(element, node);
@@ -113,7 +115,8 @@ class SignatureResolver extends MappingVisitor<FormalElementX> {
 
   void computeParameterType(FormalElementX element,
       [VariableElement fieldElement]) {
-    void computeFunctionType(FunctionExpression functionExpression) {
+    // Function-type as in `foo(int bar(String x))`
+    void computeInlineFunctionType(FunctionExpression functionExpression) {
       FunctionSignature functionSignature = SignatureResolver.analyze(
           resolution,
           scope,
@@ -135,13 +138,14 @@ class SignatureResolver extends MappingVisitor<FormalElementX> {
       assert(invariant(currentDefinitions, link.tail.isEmpty));
       if (link.head.asFunctionExpression() != null) {
         // Inline function typed parameter, like `void m(int f(String s))`.
-        computeFunctionType(link.head);
+        computeInlineFunctionType(link.head);
       } else if (link.head.asSend() != null &&
           link.head.asSend().selector.asFunctionExpression() != null) {
         // Inline function typed initializing formal or
         // parameter with default value, like `C(int this.f(String s))` or
         // `void m([int f(String s) = null])`.
-        computeFunctionType(link.head.asSend().selector.asFunctionExpression());
+        computeInlineFunctionType(
+            link.head.asSend().selector.asFunctionExpression());
       } else {
         assert(invariant(currentDefinitions,
             link.head.asIdentifier() != null || link.head.asSend() != null));
@@ -198,6 +202,15 @@ class SignatureResolver extends MappingVisitor<FormalElementX> {
     return parameter;
   }
 
+  FormalElementX createUnnamedParameter() {
+    FormalElementX parameter;
+    assert(!createRealParameters);
+    parameter = new FormalElementX.unnamed(
+          ElementKind.PARAMETER, enclosingElement, currentDefinitions);
+    computeParameterType(parameter);
+    return parameter;
+  }
+
   InitializingFormalElementX createFieldParameter(
       Send node, Expression initializer) {
     InitializingFormalElementX element;
@@ -418,7 +431,7 @@ class SignatureResolver extends MappingVisitor<FormalElementX> {
     List<Element> orderedOptionalParameters =
         visitor.optionalParameters.toList();
     if (visitor.optionalParametersAreNamed) {
-      // TODO(karlklose); replace when [visitor.optinalParameters] is a [List].
+      // TODO(karlklose); replace when [visitor.optionalParameters] is a [List].
       orderedOptionalParameters.sort((Element a, Element b) {
         return a.name.compareTo(b.name);
       });
@@ -433,7 +446,7 @@ class SignatureResolver extends MappingVisitor<FormalElementX> {
       namedParameterTypes =
           namedParameterTypesBuilder.toLink().toList(growable: false);
     } else {
-      // TODO(karlklose); replace when [visitor.optinalParameters] is a [List].
+      // TODO(karlklose); replace when [visitor.optionalParameters] is a [List].
       LinkBuilder<DartType> optionalParameterTypesBuilder =
           new LinkBuilder<DartType>();
       for (FormalElement parameter in visitor.optionalParameters) {