Report a compile-time error when a setter has not exactly one formal parameter.

sdk/lib/_internal/compiler/implementation/resolution/members.dart

Index: sdk/lib/_internal/compiler/implementation/resolution/members.dart
diff --git a/sdk/lib/_internal/compiler/implementation/resolution/members.dart b/sdk/lib/_internal/compiler/implementation/resolution/members.dart
index d30753dff35e6085cc95390c894ce77d827477dd..f9500da00df1cc7acbce37d4cff641637f600e32 100644
--- a/sdk/lib/_internal/compiler/implementation/resolution/members.dart
+++ b/sdk/lib/_internal/compiler/implementation/resolution/members.dart
@@ -3038,6 +3038,12 @@ class SignatureResolver extends CommonResolverVisitor<Element> {
       parameters = parametersBuilder.toLink();
     }
     DartType returnType = compiler.resolveReturnType(element, returnNode);
+    if (element.isSetter() && (requiredParameterCount != 1 ||
+                               visitor.optionalParameterCount != 0)) {
+      compiler.reportMessage(compiler.spanFromElement(element),

[ahe, 2012/12/05 20:17:06]

I think a better location would be:

compiler.spanFromNode(formalParameters)

[karlklose, 2012/12/06 09:13:32]

Done.

+                             MessageKind.ILLEGAL_SETTER_FORMALS.error([]),
+                             Diagnostic.ERROR);
+    }
     return new FunctionSignature(parameters,
                                  visitor.optionalParameters,
                                  requiredParameterCount,