From 1bfadba58f9cda448e46713fcb1514da0cd83961 Mon Sep 17 00:00:00 2001
From: "alexey.afanasiev" <Alexey.Afanasiev@jetbrains.com>
Date: Mon, 21 Aug 2017 13:16:36 +0300
Subject: [PATCH] IDEA-177330 @CompileStatic multiple assignment in variable
 definition should be red

---
 .../typedef/members/GrMethodBaseImpl.java      |  2 +-
 .../lang/resolve/TypeInferenceTest.groovy      | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/statements/typedef/members/GrMethodBaseImpl.java b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/statements/typedef/members/GrMethodBaseImpl.java
index 4c3f627b6ba4..d9334c1f0702 100644
--- a/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/statements/typedef/members/GrMethodBaseImpl.java
+++ b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/statements/typedef/members/GrMethodBaseImpl.java
@@ -230,7 +230,7 @@ public abstract class GrMethodBaseImpl extends GrStubElementBase<GrMethodStub> i
       if (block != null) {
         PsiType inferred = GroovyPsiManager.inferType(method, new MethodTypeInferencer(block));
         if (inferred != null) {
-          if (nominal == null || nominal.isAssignableFrom(inferred)) {
+          if (nominal == null || (nominal.isAssignableFrom(inferred) && !inferred.equals(PsiType.NULL))) {
             return inferred;
           }
         }
diff --git a/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/resolve/TypeInferenceTest.groovy b/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/resolve/TypeInferenceTest.groovy
index a75cd5b9752a..55eee5034e1f 100644
--- a/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/resolve/TypeInferenceTest.groovy
+++ b/plugins/groovy/test/org/jetbrains/plugins/groovy/lang/resolve/TypeInferenceTest.groovy
@@ -709,6 +709,24 @@ def foo(List list) {
 ''', 'java.util.List<java.util.List>')
   }
 
+  void testReturnNullWithGeneric() {
+    doTest('''
+     import groovy.transform.CompileStatic
+
+    @CompileStatic
+    class SomeClass {
+      protected List foo(String text) {
+        return null
+      }
+
+      def bar() {
+        fo<caret>o("")
+      }
+    }
+  }
+''', 'java.util.List')
+  }
+
 
   void testClassExpressions() {
     doExprTest 'String[]', 'java.lang.Class<java.lang.String[]>'