From fbc1d1a844c49a8b63dcd1339395b0015b735be4 Mon Sep 17 00:00:00 2001
From: Mikhail Glukhikh <mikhail.glukhikh@jetbrains.com>
Date: Fri, 28 Apr 2017 15:42:17 +0300
Subject: [PATCH] Clear var nullability in loops more accurately #KT-14977
 Fixed

---
 .../calls/smartcasts/DelegatingDataFlowInfo.kt    |  2 +-
 .../tests/senselessComparison/noExplicitType.kt   | 15 +++++++++++++++
 .../tests/senselessComparison/noExplicitType.txt  |  5 +++++
 .../kotlin/checkers/DiagnosticsTestGenerated.java |  6 ++++++
 4 files changed, 27 insertions(+), 1 deletion(-)
 create mode 100644 compiler/testData/diagnostics/tests/senselessComparison/noExplicitType.kt
 create mode 100644 compiler/testData/diagnostics/tests/senselessComparison/noExplicitType.txt

diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/DelegatingDataFlowInfo.kt b/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/DelegatingDataFlowInfo.kt
index 822d359278d..5e2d340c97e 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/DelegatingDataFlowInfo.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/calls/smartcasts/DelegatingDataFlowInfo.kt
@@ -146,7 +146,7 @@ internal class DelegatingDataFlowInfo private constructor(
      */
     override fun clearValueInfo(value: DataFlowValue, languageVersionSettings: LanguageVersionSettings): DataFlowInfo {
         val builder = Maps.newHashMap<DataFlowValue, Nullability>()
-        putNullability(builder, value, Nullability.UNKNOWN, languageVersionSettings)
+        putNullability(builder, value, value.immanentNullability, languageVersionSettings)
         return create(this, ImmutableMap.copyOf(builder), EMPTY_TYPE_INFO, value)
     }
 
diff --git a/compiler/testData/diagnostics/tests/senselessComparison/noExplicitType.kt b/compiler/testData/diagnostics/tests/senselessComparison/noExplicitType.kt
new file mode 100644
index 00000000000..a094a2e60e8
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/senselessComparison/noExplicitType.kt
@@ -0,0 +1,15 @@
+fun readLine() = "x"
+
+fun foo() {
+    var line = ""
+
+    while (<!SENSELESS_COMPARISON!>line != null<!>) {
+        line = readLine()
+
+        if (<!SENSELESS_COMPARISON!>line != null<!>) {
+            bar()
+        }
+    }
+}
+
+fun bar() {}
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/senselessComparison/noExplicitType.txt b/compiler/testData/diagnostics/tests/senselessComparison/noExplicitType.txt
new file mode 100644
index 00000000000..af96f9548a8
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/senselessComparison/noExplicitType.txt
@@ -0,0 +1,5 @@
+package
+
+public fun bar(): kotlin.Unit
+public fun foo(): kotlin.Unit
+public fun readLine(): kotlin.String
diff --git a/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java
index 294f6d0007c..a5d3e721156 100644
--- a/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java
@@ -19183,6 +19183,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/diagnostics/tests/senselessComparison"), Pattern.compile("^(.+)\\.kt$"), TargetBackend.ANY, true);
             }
 
+            @TestMetadata("noExplicitType.kt")
+            public void testNoExplicitType() throws Exception {
+                String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/senselessComparison/noExplicitType.kt");
+                doTest(fileName);
+            }
+
             @TestMetadata("parenthesized.kt")
             public void testParenthesized() throws Exception {
                 String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/senselessComparison/parenthesized.kt");