Tests for `void`.

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 ac7b6d847833a9eef77a2036176213907bb5d8ad..6d953ad6020c82e91ebb114cd7fb5c17b5e643f8 100644
--- a/pkg/compiler/lib/src/resolution/signatures.dart
+++ b/pkg/compiler/lib/src/resolution/signatures.dart
@@ -93,7 +93,9 @@ class SignatureResolver extends MappingVisitor<FormalElementX> {
       reporter.internalError(node, 'function type parameters not supported');
     }
     currentDefinitions = node;
-    FormalElementX element = definition.accept(this);
+    FormalElementX element = definition == null
+        ? createUnnamedParameter()  // This happens in function types.
+        : definition.accept(this);
     if (currentDefinitions.metadata != null) {
       element.metadataInternal =
           resolution.resolver.resolveMetadata(element, node);
@@ -112,7 +114,8 @@ 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,
@@ -134,13 +137,14 @@ 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));
@@ -197,6 +201,15 @@ 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;
@@ -386,7 +399,7 @@ class SignatureResolver extends MappingVisitor<FormalElementX> {
       }
       switch (asyncMarker) {
         case AsyncMarker.SYNC:
-          returnType = visitor.resolveReturnType(returnNode);
+          returnType = visitor.resolveTypeAnnotation(returnNode);
           break;
         case AsyncMarker.SYNC_STAR:
           ResolutionInterfaceType iterableType =
@@ -426,7 +439,7 @@ 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);
       });
@@ -441,7 +454,7 @@ 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<ResolutionDartType> optionalParameterTypesBuilder =
           new LinkBuilder<ResolutionDartType>();
       for (FormalElement parameter in visitor.optionalParameters) {
@@ -469,14 +482,6 @@ class SignatureResolver extends MappingVisitor<FormalElementX> {
   }
 
   ResolutionDartType resolveTypeAnnotation(TypeAnnotation annotation) {
-    ResolutionDartType type = resolveReturnType(annotation);
-    if (type.isVoid) {
-      reporter.reportErrorMessage(annotation, MessageKind.VOID_NOT_ALLOWED);
-    }
-    return type;
-  }
-
-  ResolutionDartType resolveReturnType(TypeAnnotation annotation) {
     if (annotation == null) return const ResolutionDynamicType();
     ResolutionDartType result = resolver.resolveTypeAnnotation(annotation);
     if (result == null) {