From 63366042ed06103f36f84778964d9bcad8475234 Mon Sep 17 00:00:00 2001
From: Alexander Udalov <Alexander.Udalov@jetbrains.com>
Date: Fri, 17 Oct 2014 13:21:33 +0400
Subject: [PATCH] Fix incorrect "senseless null in when" on nullable type

---
 .../PatternMatchingTypingVisitor.java         |  2 +-
 .../noSenselessNullOnNullableType.kt          | 21 ++++++++++++++
 .../noSenselessNullOnNullableType.txt         | 28 +++++++++++++++++++
 .../checkers/JetDiagnosticsTestGenerated.java |  6 ++++
 4 files changed, 56 insertions(+), 1 deletion(-)
 create mode 100644 compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/noSenselessNullOnNullableType.kt
 create mode 100644 compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/noSenselessNullOnNullableType.txt

diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/PatternMatchingTypingVisitor.java b/compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/PatternMatchingTypingVisitor.java
index 13b7be36ffb..d2d4ff18cd5 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/PatternMatchingTypingVisitor.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/PatternMatchingTypingVisitor.java
@@ -320,7 +320,7 @@ public class PatternMatchingTypingVisitor extends ExpressionTypingVisitor {
         }
 
         // check if the pattern is essentially a 'null' expression
-        if (KotlinBuiltIns.getInstance().isNullableNothing(type) && !subjectType.isNullable()) {
+        if (KotlinBuiltIns.getInstance().isNullableNothing(type) && !TypeUtils.isNullableType(subjectType)) {
             context.trace.report(SENSELESS_NULL_IN_WHEN.on(reportErrorOn));
         }
     }
diff --git a/compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/noSenselessNullOnNullableType.kt b/compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/noSenselessNullOnNullableType.kt
new file mode 100644
index 00000000000..b0624fd098e
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/noSenselessNullOnNullableType.kt
@@ -0,0 +1,21 @@
+// FILE: A.java
+
+class A {
+    enum Empty {}
+
+    static Empty foo() { return null; }
+}
+
+// FILE: 1.kt
+
+fun bar() = when (A.foo()) {
+    null -> "null"
+    else -> "else"
+}
+
+fun <T : Number?> baz(t: T) = when (t) {
+    is Int -> "int"
+    is Long -> "long"
+    null -> "null"
+    else -> "else"
+}
diff --git a/compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/noSenselessNullOnNullableType.txt b/compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/noSenselessNullOnNullableType.txt
new file mode 100644
index 00000000000..cb1f52fae89
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/noSenselessNullOnNullableType.txt
@@ -0,0 +1,28 @@
+package
+
+internal fun bar(): kotlin.String
+internal fun </*0*/ T : kotlin.Number?> baz(/*0*/ t: T): kotlin.String
+
+public/*package*/ open class A {
+    public/*package*/ constructor A()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+    public/*package*/ final enum class Empty : kotlin.Enum<A.Empty!> {
+        public/*package*/ constructor Empty()
+        public final override /*1*/ /*fake_override*/ fun compareTo(/*0*/ other: A.Empty!): kotlin.Int
+        public final override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+        public final override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+        public final override /*1*/ /*fake_override*/ fun name(): kotlin.String
+        public final override /*1*/ /*fake_override*/ fun ordinal(): kotlin.Int
+        public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+
+        // Static members
+        public final /*synthesized*/ fun valueOf(/*0*/ value: kotlin.String): A.Empty
+        public final /*synthesized*/ fun values(): kotlin.Array<A.Empty>
+    }
+
+    // Static members
+    public/*package*/ open fun foo(): A.Empty!
+}
\ No newline at end of file
diff --git a/compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java b/compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java
index 59f521fa499..84e62e5d8ab 100644
--- a/compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java
+++ b/compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java
@@ -7031,6 +7031,12 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                 doTest(fileName);
             }
             
+            @TestMetadata("noSenselessNullOnNullableType.kt")
+            public void testNoSenselessNullOnNullableType() throws Exception {
+                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/noSenselessNullOnNullableType.kt");
+                doTest(fileName);
+            }
+            
             @TestMetadata("noUnnecessaryNotNullAssertionOnErrorType.kt")
             public void testNoUnnecessaryNotNullAssertionOnErrorType() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/nullabilityAndSmartCasts/noUnnecessaryNotNullAssertionOnErrorType.kt");