From 4f678fa85cc3ff78319c5c6cff4fbcd2f5a9fe86 Mon Sep 17 00:00:00 2001
From: Dmitry Neverov <dmitry.neverov@gmail.com>
Date: Wed, 28 Jun 2017 07:31:09 +0300
Subject: [PATCH] Do not suggest !! on expression which is always null

Related to KT-14643
---
 .../kotlin/idea/quickfix/ExclExclCallFixes.kt   | 17 +++++++++++++++--
 .../quickfix/addExclExclCall/nullExpression.kt  | 11 +++++++++++
 .../idea/quickfix/QuickFixTestGenerated.java    |  6 ++++++
 3 files changed, 32 insertions(+), 2 deletions(-)
 create mode 100644 idea/testData/quickfix/addExclExclCall/nullExpression.kt

diff --git a/idea/src/org/jetbrains/kotlin/idea/quickfix/ExclExclCallFixes.kt b/idea/src/org/jetbrains/kotlin/idea/quickfix/ExclExclCallFixes.kt
index 04d843b1e3b..664509c0ecc 100644
--- a/idea/src/org/jetbrains/kotlin/idea/quickfix/ExclExclCallFixes.kt
+++ b/idea/src/org/jetbrains/kotlin/idea/quickfix/ExclExclCallFixes.kt
@@ -30,12 +30,15 @@ import org.jetbrains.kotlin.diagnostics.Diagnostic
 import org.jetbrains.kotlin.diagnostics.Errors
 import org.jetbrains.kotlin.idea.KotlinBundle
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
+import org.jetbrains.kotlin.idea.caches.resolve.findModuleDescriptor
 import org.jetbrains.kotlin.idea.intentions.branchedTransformations.isNullExpression
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
 import org.jetbrains.kotlin.resolve.calls.resolvedCallUtil.getImplicitReceiverValue
+import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValueFactory
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
 import org.jetbrains.kotlin.types.TypeUtils
 import org.jetbrains.kotlin.types.typeUtil.isSubtypeOf
@@ -128,11 +131,21 @@ class AddExclExclCallFix(psiElement: PsiElement, val checkImplicitReceivers: Boo
             }
         }
         else if (psiElement is KtExpression) {
-            if (checkImplicitReceivers && psiElement.getResolvedCall(psiElement.analyze())?.getImplicitReceiverValue() != null) {
+            val context = psiElement.analyze()
+            if (checkImplicitReceivers && psiElement.getResolvedCall(context)?.getImplicitReceiverValue() != null) {
                 val expressionToReplace = psiElement.parent as? KtCallExpression ?: psiElement
                 expressionToReplace.expressionForCall(implicitReceiver = true)
             }
-            else psiElement.expressionForCall()
+            else {
+                context[BindingContext.EXPRESSION_TYPE_INFO, psiElement]?.let {
+                    val type = it.type
+                    if (type != null) {
+                        val nullability = it.dataFlowInfo.getStableNullability(DataFlowValueFactory.createDataFlowValue(psiElement, type, context, psiElement.findModuleDescriptor()))
+                        if (!nullability.canBeNonNull()) return null
+                    }
+                }
+                psiElement.expressionForCall()
+            }
         }
         else {
             null
diff --git a/idea/testData/quickfix/addExclExclCall/nullExpression.kt b/idea/testData/quickfix/addExclExclCall/nullExpression.kt
new file mode 100644
index 00000000000..0da26f48e2e
--- /dev/null
+++ b/idea/testData/quickfix/addExclExclCall/nullExpression.kt
@@ -0,0 +1,11 @@
+// "Add non-null asserted (!!) call" "false"
+// ACTION: Add 'toString()' call
+// ACTION: Change type of 'x' to 'String?'
+// ACTION: Remove braces from 'if' statement
+// ERROR: Type mismatch: inferred type is String? but String was expected
+
+fun foo(arg: String?) {
+    if (arg == null) {
+        val x: String = arg<caret>
+    }
+}
\ No newline at end of file
diff --git a/idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java b/idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java
index da2eb4612a5..04acfc59723 100644
--- a/idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java
+++ b/idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java
@@ -272,6 +272,12 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
             doTest(fileName);
         }
 
+        @TestMetadata("nullExpression.kt")
+        public void testNullExpression() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/addExclExclCall/nullExpression.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("operationIn.kt")
         public void testOperationIn() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/addExclExclCall/operationIn.kt");