From a97212d84568c9180608f31e8cef1b51feeec177 Mon Sep 17 00:00:00 2001
From: Anna Kozlova <anna.kozlova@jetbrains.com>
Date: Wed, 30 May 2018 12:58:14 +0300
Subject: [PATCH] completion: infer ? super for inference variables with lower
 bounds

IDEA-45672
---
 .../resolve/CompletionParameterTypeInferencePolicy.java   | 2 +-
 .../source/resolve/graphInference/InferenceSession.java   | 2 +-
 .../smartType/ExpectedSuperOfLowerBound-out.java          | 8 ++++++++
 .../completion/smartType/ExpectedSuperOfLowerBound.java   | 8 ++++++++
 .../codeInsight/completion/SmartType18CompletionTest.java | 5 +++++
 5 files changed, 23 insertions(+), 2 deletions(-)
 create mode 100644 java/java-tests/testData/codeInsight/completion/smartType/ExpectedSuperOfLowerBound-out.java
 create mode 100644 java/java-tests/testData/codeInsight/completion/smartType/ExpectedSuperOfLowerBound.java

diff --git a/java/java-impl/src/com/intellij/psi/impl/source/resolve/CompletionParameterTypeInferencePolicy.java b/java/java-impl/src/com/intellij/psi/impl/source/resolve/CompletionParameterTypeInferencePolicy.java
index 350b24646f99..9100174f0f3f 100644
--- a/java/java-impl/src/com/intellij/psi/impl/source/resolve/CompletionParameterTypeInferencePolicy.java
+++ b/java/java-impl/src/com/intellij/psi/impl/source/resolve/CompletionParameterTypeInferencePolicy.java
@@ -55,7 +55,7 @@ public class CompletionParameterTypeInferencePolicy extends ProcessCandidatePara
 
   @Override
   public PsiType adjustInferredType(PsiManager manager, PsiType guess, ConstraintType constraintType) {
-    if (guess != null && !(guess instanceof PsiWildcardType)) {
+    if (guess != null && !(guess instanceof PsiWildcardType) && guess != PsiType.NULL) {
       if (constraintType == ConstraintType.SUPERTYPE) return PsiWildcardType.createExtends(manager, guess);
       else if (constraintType == ConstraintType.SUBTYPE) return PsiWildcardType.createSuper(manager, guess);
     }
diff --git a/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java
index 850420f11d0d..0424f2fc8d47 100644
--- a/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java
+++ b/java/java-psi-impl/src/com/intellij/psi/impl/source/resolve/graphInference/InferenceSession.java
@@ -1157,7 +1157,7 @@ public class InferenceSession {
   private PsiType checkBoundsConsistency(PsiSubstitutor substitutor, InferenceVariable var) {
     PsiType eqBound = getEqualsBound(var, substitutor);
     if (eqBound != PsiType.NULL && eqBound instanceof PsiPrimitiveType) return PsiType.NULL;
-    final PsiType lowerBound = getLowerBound(var, substitutor);
+    final PsiType lowerBound = myPolicy.adjustInferredType(myManager, getLowerBound(var, substitutor), ConstraintType.SUBTYPE);
     final PsiType upperBound = getUpperBound(var, substitutor);
     PsiType type;
     if (eqBound != PsiType.NULL && (myErased || eqBound != null)) {
diff --git a/java/java-tests/testData/codeInsight/completion/smartType/ExpectedSuperOfLowerBound-out.java b/java/java-tests/testData/codeInsight/completion/smartType/ExpectedSuperOfLowerBound-out.java
new file mode 100644
index 000000000000..99f32602da26
--- /dev/null
+++ b/java/java-tests/testData/codeInsight/completion/smartType/ExpectedSuperOfLowerBound-out.java
@@ -0,0 +1,8 @@
+import java.util.*;
+class MyTest {
+    <T> void addIfNotNull(T t, Collection<T> collection) {}
+    {
+        List<Object> l = null;
+        addIfNotNull("someString", l);
+    }
+}
\ No newline at end of file
diff --git a/java/java-tests/testData/codeInsight/completion/smartType/ExpectedSuperOfLowerBound.java b/java/java-tests/testData/codeInsight/completion/smartType/ExpectedSuperOfLowerBound.java
new file mode 100644
index 000000000000..ebd849392420
--- /dev/null
+++ b/java/java-tests/testData/codeInsight/completion/smartType/ExpectedSuperOfLowerBound.java
@@ -0,0 +1,8 @@
+import java.util.*;
+class MyTest {
+    <T> void addIfNotNull(T t, Collection<T> collection) {}
+    {
+        List<Object> l = null;
+        addIfNotNull("someString", <caret>);
+    }
+}
\ No newline at end of file
diff --git a/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/SmartType18CompletionTest.java b/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/SmartType18CompletionTest.java
index 02a6821afb32..d8c9221ba182 100644
--- a/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/SmartType18CompletionTest.java
+++ b/java/java-tests/testSrc/com/intellij/java/codeInsight/completion/SmartType18CompletionTest.java
@@ -219,6 +219,11 @@ public void testConvertToObjectStream() {
   }
 
   public void testCollectionsEmptyMap() { doTest(true); }
+  public void testExpectedSuperOfLowerBound() { 
+    configureByTestName();
+    myFixture.complete(CompletionType.SMART, 1);
+    checkResultByFile("/" + getTestName(false) + "-out.java");
+  }
 
   private void doTest() {
     doTest(true);