From 6155526cce4e21b8732d2d95b57e0c852787640a Mon Sep 17 00:00:00 2001
From: Daniil Ovchinnikov <daniil.ovchinnikov@jetbrains.com>
Date: Wed, 23 Jan 2019 13:48:31 +0300
Subject: [PATCH] [groovy] dfa: check reassigned type in @CompileStatic
 (IDEA-186753)

---
 .../expressions/GrReferenceExpressionImpl.java     | 14 +++++++++++++-
 .../groovy/lang/resolve/TypeInferenceTest.groovy   | 13 +++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/statements/expressions/GrReferenceExpressionImpl.java b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/statements/expressions/GrReferenceExpressionImpl.java
index 5b4f7e6b1f5d..d8c31c8ba92d 100644
--- a/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/statements/expressions/GrReferenceExpressionImpl.java
+++ b/plugins/groovy/groovy-psi/src/org/jetbrains/plugins/groovy/lang/psi/impl/statements/expressions/GrReferenceExpressionImpl.java
@@ -310,7 +310,19 @@ public class GrReferenceExpressionImpl extends GrReferenceElementImpl<GrExpressi
 
     Boolean reassigned = GrReassignedLocalVarsChecker.isReassignedVar(refExpr);
     if (reassigned != null && reassigned.booleanValue()) {
-      return GrReassignedLocalVarsChecker.getReassignedVarType(refExpr, true);
+      PsiType reassignedType = GrReassignedLocalVarsChecker.getReassignedVarType(refExpr, true);
+      if (reassignedType == null) {
+        return nominal;
+      }
+      else if (nominal == null) {
+        return reassignedType;
+      }
+      else if (TypeConversionUtil.isAssignable(TypeConversionUtil.erasure(nominal), reassignedType, false)) {
+        return reassignedType;
+      }
+      else {
+        return nominal;
+      }
     }
 
     final PsiType inferred = getInferredTypes(refExpr, resolved);
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 87398403fc5e..757f56c67d43 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
@@ -1091,4 +1091,17 @@ while (condition) {
 <caret>prevParent
 ''', 'java.lang.String'
   }
+
+  void 'test String variable assigned with GString inside closure @CS'() {
+    doTest '''\
+@groovy.transform.CompileStatic
+def test() {
+    String key
+    return {
+        key = "hi ${"there"}"
+        <caret>key
+    }
+}
+''', JAVA_LANG_STRING
+  }
 }