From 3e38870ecc3fda80609c774d480235dae2ed8af2 Mon Sep 17 00:00:00 2001
From: Andrey Breslav <andrey.breslav@jetbrains.com>
Date: Thu, 25 Oct 2012 07:15:30 +0400
Subject: [PATCH] KT-2991 Don't generate UNNECESSARY_NOT_NULL_ASSERTION on
 variables of generic type T:Any?

 #KT-2991 Fixed
---
 .../expressions/BasicExpressionTypingVisitor.java | 15 +++++----------
 .../nullAssertOnTypeWithNullableUpperBound.kt     | 14 ++++++++++++++
 .../jet/checkers/JetDiagnosticsTestGenerated.java |  5 +++++
 3 files changed, 24 insertions(+), 10 deletions(-)
 create mode 100644 compiler/testData/diagnostics/tests/nullableTypes/nullAssertOnTypeWithNullableUpperBound.kt

diff --git a/compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/BasicExpressionTypingVisitor.java b/compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/BasicExpressionTypingVisitor.java
index 2ce106a0817..a1b4d401b2f 100644
--- a/compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/BasicExpressionTypingVisitor.java
+++ b/compiler/frontend/src/org/jetbrains/jet/lang/types/expressions/BasicExpressionTypingVisitor.java
@@ -28,7 +28,9 @@ import org.jetbrains.jet.lang.descriptors.*;
 import org.jetbrains.jet.lang.diagnostics.Errors;
 import org.jetbrains.jet.lang.psi.*;
 import org.jetbrains.jet.lang.resolve.*;
-import org.jetbrains.jet.lang.resolve.calls.*;
+import org.jetbrains.jet.lang.resolve.calls.CallMaker;
+import org.jetbrains.jet.lang.resolve.calls.OverloadResolutionResults;
+import org.jetbrains.jet.lang.resolve.calls.OverloadResolutionResultsUtil;
 import org.jetbrains.jet.lang.resolve.calls.autocasts.DataFlowInfo;
 import org.jetbrains.jet.lang.resolve.calls.autocasts.DataFlowValue;
 import org.jetbrains.jet.lang.resolve.calls.autocasts.DataFlowValueFactory;
@@ -918,15 +920,8 @@ public class BasicExpressionTypingVisitor extends ExpressionTypingVisitor {
     private boolean isKnownToBeNotNull(JetExpression expression, ExpressionTypingContext context) {
         JetType type = context.trace.get(EXPRESSION_TYPE, expression);
         assert type != null : "This method is only supposed to be called when the type is not null";
-        if (!type.isNullable()) return true;
-        List<JetType> possibleTypes = context.dataFlowInfo
-            .getPossibleTypes(DataFlowValueFactory.INSTANCE.createDataFlowValue(expression, type, context.trace.getBindingContext()));
-        for (JetType possibleType : possibleTypes) {
-            if (!possibleType.isNullable()) {
-                return true;
-            }
-        }
-        return false;
+        DataFlowValue dataFlowValue = DataFlowValueFactory.INSTANCE.createDataFlowValue(expression, type, context.trace.getBindingContext());
+        return !context.dataFlowInfo.getNullability(dataFlowValue).canBeNull();
     }
 
     public void checkLValue(BindingTrace trace, JetExpression expression) {
diff --git a/compiler/testData/diagnostics/tests/nullableTypes/nullAssertOnTypeWithNullableUpperBound.kt b/compiler/testData/diagnostics/tests/nullableTypes/nullAssertOnTypeWithNullableUpperBound.kt
new file mode 100644
index 00000000000..2b51253a6c2
--- /dev/null
+++ b/compiler/testData/diagnostics/tests/nullableTypes/nullAssertOnTypeWithNullableUpperBound.kt
@@ -0,0 +1,14 @@
+fun <T> test(t: T): T {
+    if (t != null) {
+        return t<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>
+    }
+    return t!!
+}
+
+fun <T> T.testThis(): String {
+    if (this != null) {
+        return this<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.toString()
+    }
+    return this!!.toString()
+}
+
diff --git a/compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java b/compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java
index 957d503ea77..95779106db5 100644
--- a/compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java
+++ b/compiler/tests/org/jetbrains/jet/checkers/JetDiagnosticsTestGenerated.java
@@ -2304,6 +2304,11 @@ public class JetDiagnosticsTestGenerated extends AbstractDiagnosticsTestWithEage
                 doTest("compiler/testData/diagnostics/tests/nullableTypes/baseWithNullableUpperBound.kt");
             }
             
+            @TestMetadata("nullAssertOnTypeWithNullableUpperBound.kt")
+            public void testNullAssertOnTypeWithNullableUpperBound() throws Exception {
+                doTest("compiler/testData/diagnostics/tests/nullableTypes/nullAssertOnTypeWithNullableUpperBound.kt");
+            }
+            
             @TestMetadata("redundantNullable.kt")
             public void testRedundantNullable() throws Exception {
                 doTest("compiler/testData/diagnostics/tests/nullableTypes/redundantNullable.kt");