diff --git a/plugins/groovy/src/org/jetbrains/plugins/groovy/codeInspection/assignment/GroovyAssignabilityCheckInspection.java b/plugins/groovy/src/org/jetbrains/plugins/groovy/codeInspection/assignment/GroovyAssignabilityCheckInspection.java
index e62afa172b81..00532b3fcf86 100644
--- a/plugins/groovy/src/org/jetbrains/plugins/groovy/codeInspection/assignment/GroovyAssignabilityCheckInspection.java
+++ b/plugins/groovy/src/org/jetbrains/plugins/groovy/codeInspection/assignment/GroovyAssignabilityCheckInspection.java
@@ -264,7 +264,8 @@ public class GroovyAssignabilityCheckInspection extends BaseInspection {
       final PsiElement constructor = constructorResolveResult.getElement();
 
       if (constructor != null) {
-        checkConstructorApplicability(constructorResolveResult, refElement);
+        if (!checkConstructorApplicability(constructorResolveResult, refElement)) return;
+        if (!checkUnknownParams(refElement)) return;
       }
       else {
         final GroovyResolveResult[] results = constructorCall.multiResolveConstructor();
@@ -275,7 +276,7 @@ public class GroovyAssignabilityCheckInspection extends BaseInspection {
               if (!checkConstructorApplicability(result, refElement)) return;
             }
           }
-
+          if (!checkUnknownParams(refElement)) return;
           registerError(getElementToHighlight(refElement, argList), GroovyBundle.message("constructor.call.is.ambiguous"));
         }
         else {
@@ -419,12 +420,12 @@ public class GroovyAssignabilityCheckInspection extends BaseInspection {
         final PsiType type = referenceExpression.getType();
         if (resolved != null ) {
           if (resolved instanceof PsiMethod && !resolveResult.isInvokedOnProperty()) {
-            checkMethodApplicability(resolveResult, referenceExpression);
+            if (!checkMethodApplicability(resolveResult, referenceExpression)) return;
           }
           else {
-            checkCallApplicability(type, referenceExpression);
+            if (!checkCallApplicability(type, referenceExpression)) return;
           }
-
+          if (!checkUnknownParams(referenceExpression)) return;
         }
         else if (results.length > 0) {
           for (GroovyResolveResult result : results) {
@@ -436,6 +437,7 @@ public class GroovyAssignabilityCheckInspection extends BaseInspection {
               if (!checkCallApplicability(type, referenceExpression)) return;
             }
           }
+          if (!checkUnknownParams(referenceExpression)) return;
 
           registerError(getElementToHighlight(referenceExpression, PsiUtil.getArgumentsList(referenceExpression)),
                         GroovyBundle.message("method.call.is.ambiguous"));
@@ -443,6 +445,20 @@ public class GroovyAssignabilityCheckInspection extends BaseInspection {
       }
     }
 
+    private boolean checkUnknownParams(PsiElement place) {
+      PsiType[] args = PsiUtil.getArgumentTypes(place, true);
+      if (args == null) return true;
+
+      for (PsiType arg : args) {
+        if (arg == null) {
+          registerError(getElementToHighlight(place, PsiUtil.getArgumentsList(place)), GroovyBundle.message("cannot.infer.argument.types"),
+                        LocalQuickFix.EMPTY_ARRAY, ProblemHighlightType.WEAK_WARNING);
+          return false;
+        }
+      }
+      return true;
+    }
+
     private boolean checkCannotInferArgumentTypes(PsiElement referenceExpression) {
       if (PsiUtil.getArgumentTypes(referenceExpression, true) != null) return false;
 
@@ -553,10 +569,12 @@ public class GroovyAssignabilityCheckInspection extends BaseInspection {
           PsiElement resolved = result.getElement();
           if (resolved instanceof PsiMethod && !result.isInvokedOnProperty()) {
             if (!checkMethodApplicability(result, invokedExpr)) return false;
+            if (!checkUnknownParams(invokedExpr)) return false;
           }
           else if (resolved instanceof PsiField) {
             if (!checkCallApplicability(((PsiField)resolved).getType(), invokedExpr)) return false;
           }
+          if (!checkUnknownParams(invokedExpr)) return false;
         }
         if (calls.length == 0 && !(invokedExpr instanceof GrString)) {
           registerCannotApplyError(invokedExpr, argumentTypes, invokedExpr.getText());
diff --git a/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/impl/statements/expressions/TypesUtil.java b/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/impl/statements/expressions/TypesUtil.java
index 426bc7760f18..c18d68533059 100644
--- a/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/impl/statements/expressions/TypesUtil.java
+++ b/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/impl/statements/expressions/TypesUtil.java
@@ -299,7 +299,7 @@ public class TypesUtil {
       }
     }
 
-    if (isClassType(rType, GroovyCommonClassNames.GROOVY_LANG_GSTRING)) {
+    if (isClassType(rType, GROOVY_LANG_GSTRING)) {
       if (isAssignable(lType, GroovyPsiManager.getInstance(manager.getProject()).createTypeByFQClassName(JAVA_LANG_STRING, scope), manager, scope)) {
         return true;
       }
@@ -584,9 +584,9 @@ public class TypesUtil {
   public static PsiClassType createListType(@NotNull PsiClass elements) {
     JavaPsiFacade facade = JavaPsiFacade.getInstance(elements.getProject());
     GlobalSearchScope resolveScope = elements.getResolveScope();
-    PsiClass listClass = facade.findClass(CommonClassNames.JAVA_UTIL_LIST, resolveScope);
+    PsiClass listClass = facade.findClass(JAVA_UTIL_LIST, resolveScope);
     if (listClass == null) {
-      return facade.getElementFactory().createTypeByFQClassName(CommonClassNames.JAVA_UTIL_LIST, resolveScope);
+      return facade.getElementFactory().createTypeByFQClassName(JAVA_UTIL_LIST, resolveScope);
     }
     return facade.getElementFactory().createType(listClass, facade.getElementFactory().createType(elements));
   }
@@ -596,12 +596,12 @@ public class TypesUtil {
     JavaPsiFacade facade = JavaPsiFacade.getInstance(context.getProject());
     GlobalSearchScope resolveScope = context.getResolveScope();
 
-    PsiClass setClass = facade.findClass(CommonClassNames.JAVA_UTIL_SET, resolveScope);
+    PsiClass setClass = facade.findClass(JAVA_UTIL_SET, resolveScope);
     if (setClass != null) {
       return facade.getElementFactory().createType(setClass, type);
     }
 
-    return facade.getElementFactory().createTypeByFQClassName(CommonClassNames.JAVA_UTIL_SET, resolveScope);
+    return facade.getElementFactory().createTypeByFQClassName(JAVA_UTIL_SET, resolveScope);
   }
 
   public static Map<String, PsiClass> getSuperClassesWithCache(@NotNull PsiClass aClass) {
diff --git a/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/impl/types/GrClosureSignatureUtil.java b/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/impl/types/GrClosureSignatureUtil.java
index b22bff737a58..1ab1ea08ceae 100644
--- a/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/impl/types/GrClosureSignatureUtil.java
+++ b/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/impl/types/GrClosureSignatureUtil.java
@@ -52,6 +52,7 @@ import java.util.*;
 /**
  * @author Maxim.Medvedev
  */
+@SuppressWarnings("unchecked")
 public class GrClosureSignatureUtil {
   private GrClosureSignatureUtil() {
   }
@@ -549,7 +550,7 @@ public class GrClosureSignatureUtil {
 
     for (GrExpression expression : expressionArgs) {
       PsiType type = expression.getType();
-      if (expression instanceof GrNewExpression && com.intellij.psi.util.PsiUtil.resolveClassInType(type) == null) {
+      if (partial && expression instanceof GrNewExpression && com.intellij.psi.util.PsiUtil.resolveClassInType(type) == null) {
         type = null;
       }
       if (eraseArgs) {
@@ -649,24 +650,6 @@ public class GrClosureSignatureUtil {
     return generateAllMethodSignaturesByClosureSignature(name, signature, PsiTypeParameter.EMPTY_ARRAY, PsiSubstitutor.EMPTY);
   }
 
-  @Nullable
-  public static PsiType getTypeByTypeArg(ArgInfo<PsiType> arg, PsiManager manager, GlobalSearchScope resolveScope) {
-    if (arg.isMultiArg) {
-      if (arg.args.size() == 0) return PsiType.getJavaLangObject(manager, resolveScope).createArrayType();
-      PsiType leastUpperBound = null;
-
-      for (PsiType type : arg.args) {
-        leastUpperBound = TypesUtil.getLeastUpperBoundNullable(leastUpperBound, type, manager);
-      }
-      if (leastUpperBound == null) return null;
-      return leastUpperBound.createArrayType();
-    }
-    else {
-      if (arg.args.size() > 0) return arg.args.get(0);
-      return null;
-    }
-  }
-
   @Nullable
   public static PsiType getTypeByArg(ArgInfo<PsiElement> arg, PsiManager manager, GlobalSearchScope resolveScope) {
     if (arg.isMultiArg) {
diff --git a/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/util/PsiUtil.java b/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/util/PsiUtil.java
index df8ac872bf12..a6a832255035 100644
--- a/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/util/PsiUtil.java
+++ b/plugins/groovy/src/org/jetbrains/plugins/groovy/lang/psi/util/PsiUtil.java
@@ -251,7 +251,7 @@ public class PsiUtil {
       }
       else {
         if (type == null) {
-          result.add(nullAsBottom ? PsiType.NULL : TypesUtil.getJavaLangObject(expression));
+          result.add(nullAsBottom ? null : TypesUtil.getJavaLangObject(expression));
         }
         else {
           if (stopAt == expression) {
diff --git a/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/GroovyHighlightingTest.groovy b/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/GroovyHighlightingTest.groovy
index 575ad2e4d3c1..3fffb9539d8f 100644
--- a/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/GroovyHighlightingTest.groovy
+++ b/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/GroovyHighlightingTest.groovy
@@ -84,7 +84,7 @@ public class GroovyHighlightingTest extends LightCodeInsightFixtureTestCase {
 
   private void doTest(InspectionProfileEntry... tools) {
     myFixture.enableInspections(tools);
-    myFixture.testHighlighting(true, false, false, getTestName(false) + ".groovy");
+    myFixture.testHighlighting(true, false, true, getTestName(false) + ".groovy");
   }
 
   public void testCircularInheritance() throws Throwable {
@@ -477,11 +477,11 @@ class A {
     doTest(new GroovyUnresolvedAccessInspection());
   }
 
-  public void testUnknownVarInArgList() {
+  public void testImplicitEnumCoercion() {
     doTest(new GroovyAssignabilityCheckInspection());
   }
-  
-  public void testImplicitEnumCoercion() {
+
+  public void testUnknownVarInArgList() {
     doTest(new GroovyAssignabilityCheckInspection());
   }
 
diff --git a/plugins/groovy/test/org/jetbrains/plugins/groovy/spock/SpockTest.groovy b/plugins/groovy/test/org/jetbrains/plugins/groovy/spock/SpockTest.groovy
index 526c9ba3825c..c0709e8e3860 100644
--- a/plugins/groovy/test/org/jetbrains/plugins/groovy/spock/SpockTest.groovy
+++ b/plugins/groovy/test/org/jetbrains/plugins/groovy/spock/SpockTest.groovy
@@ -1,12 +1,11 @@
 package org.jetbrains.plugins.groovy.spock
 
-import com.intellij.testFramework.fixtures.LightCodeInsightFixtureTestCase
 import com.intellij.codeInsight.lookup.LookupElement
-import com.intellij.util.containers.CollectionFactory
-import com.intellij.psi.PsiFile
-
-import com.intellij.psi.PsiVariable
 import com.intellij.psi.CommonClassNames
+import com.intellij.psi.PsiFile
+import com.intellij.psi.PsiVariable
+import com.intellij.testFramework.fixtures.LightCodeInsightFixtureTestCase
+import com.intellij.util.containers.CollectionFactory
 import org.jetbrains.plugins.groovy.codeInspection.assignment.GroovyAssignabilityCheckInspection
 import org.jetbrains.plugins.groovy.codeInspection.untypedUnresolvedAccess.GroovyUnresolvedAccessInspection
 
@@ -203,13 +202,13 @@ class FooSpec extends spock.lang.Specification {
   public void testVariable_resolved() {
     myFixture.enableInspections(GroovyAssignabilityCheckInspection, GroovyUnresolvedAccessInspection)
 
-    myFixture.configureByText("FooSpec.groovy", """
+    myFixture.configureByText("FooSpec.groovy", """\
 class FooSpec extends spock.lang.Specification {
   def "foo test"() {
-    String subscriber = <warning>Mock</warning>()
-    then: (0.._) * subscriber.concat(_)
-      subscriber.concat(<warning>asdasdasd</warning>)
-      subscriber.concat<warning>(23)</warning>
+    String subscriber = <warning descr="Can not resolve symbol 'Mock'">Mock</warning>()
+    then: (0.._) * subscriber.concat<weak_warning descr="Cannot infer argument types">(_)</weak_warning>
+      subscriber.concat<weak_warning descr="Cannot infer argument types">(<warning descr="Can not resolve symbol 'asdasdasd'">asdasdasd</warning>)</weak_warning>
+      subscriber.concat<warning descr="'concat' in 'java.lang.String' cannot be applied to '(java.lang.Integer)'">(23)</warning>
   }
 }
 """)
diff --git a/plugins/groovy/testdata/highlighting/ImplicitEnumCoercion.groovy b/plugins/groovy/testdata/highlighting/ImplicitEnumCoercion.groovy
index a1bc879d0237..98f3189a8815 100644
--- a/plugins/groovy/testdata/highlighting/ImplicitEnumCoercion.groovy
+++ b/plugins/groovy/testdata/highlighting/ImplicitEnumCoercion.groovy
@@ -5,5 +5,5 @@ enum My {
 My var = 'foo'
 var = <warning descr="Cannot find enum constant 'fail' in enum 'My'">'fail'</warning>
 
-var = "fo"+"o"
-var="fo${'o'}"
+var = <weak_warning descr="Cannot assign string to enum 'My'">"fo"+"o"</weak_warning>
+var=<weak_warning descr="Cannot assign string to enum 'My'">"fo${'o'}"</weak_warning>
diff --git a/plugins/groovy/testdata/highlighting/SpreadArguments.groovy b/plugins/groovy/testdata/highlighting/SpreadArguments.groovy
index bcfecaae36fc..529191225a34 100644
--- a/plugins/groovy/testdata/highlighting/SpreadArguments.groovy
+++ b/plugins/groovy/testdata/highlighting/SpreadArguments.groovy
@@ -4,5 +4,4 @@ foo(1, 2, '3')
 foo(1, *[2, '3'])
 foo<warning descr="'foo' in 'SpreadArguments' cannot be applied to '(java.lang.Integer, java.lang.Integer, java.lang.Integer)'">(1, *[2, 3])</warning>
 def list = new ArrayList()
-foo(1, *list)
-
+foo<weak_warning descr="Cannot infer argument types">(1, *list)</weak_warning>
diff --git a/plugins/groovy/testdata/highlighting/UnknownVarInArgList.groovy b/plugins/groovy/testdata/highlighting/UnknownVarInArgList.groovy
index 4ed8ca33a0dc..028b03609637 100644
--- a/plugins/groovy/testdata/highlighting/UnknownVarInArgList.groovy
+++ b/plugins/groovy/testdata/highlighting/UnknownVarInArgList.groovy
@@ -1,7 +1,7 @@
 def foo(Date d) {}
 
 def a = unknown
-foo(a)
+foo<weak_warning descr="Cannot infer argument types">(a)</weak_warning>
 foo<warning descr="'foo' in 'UnknownVarInArgList' cannot be applied to '(java.lang.Integer)'">(1)</warning>
 
 
@@ -10,4 +10,4 @@ def abc(Date d){}
 def abc(int i) {}
 
 def x = unknown2
-abc<warning descr="'abc' in 'UnknownVarInArgList' cannot be applied to '(null)'">(x)</warning>
\ No newline at end of file
+abc<weak_warning descr="Cannot infer argument types">(x)</weak_warning>
\ No newline at end of file