Ignoring alternative signature annotation if it has syntax errors.

compiler/frontend.java/src/org/jetbrains/jet/lang/resolve/java/JavaDescriptorResolver.java

@@ -1622,6 +1622,11 @@ public class JavaDescriptorResolver implements DependencyClassByQualifiedNameRes
         String signature = method.getSignatureAnnotation().signature();
         if (!signature.isEmpty()) {
             JetNamedFunction altFunDeclaration = JetPsiFactory.createFunction(project, signature);
+            List<PsiErrorElement> syntaxErrors = AnalyzingUtils.getSyntaxErrorRanges(altFunDeclaration);
+            if (!syntaxErrors.isEmpty()) {
+                // TODO report syntax error as diagnostic when method is used
+            }
+            else {
                 valueParameterDescriptors = AlternativeSignatureParsing
                         .computeAlternativeValueParameters(valueParameterDescriptors, altFunDeclaration);
                 JetTypeReference returnTypeRef = altFunDeclaration.getReturnTypeRef();
@@ -1630,6 +1635,7 @@ public class JavaDescriptorResolver implements DependencyClassByQualifiedNameRes
                 }
                 methodTypeParameters = AlternativeSignatureParsing.computeAlternativeTypeParameters(methodTypeParameters, altFunDeclaration);
             }
+        }
 
         functionDescriptorImpl.initialize(
                 valueParameterDescriptors.receiverType,