Support smart casts after if (nullable ?: boolean) #KT-8492 Fixed

compiler/frontend/src/org/jetbrains/kotlin/types/expressions/DataFlowAnalyzer.java

@@ -22,6 +22,7 @@ import com.intellij.psi.tree.IElementType;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns;
+import org.jetbrains.kotlin.config.LanguageFeature;
 import org.jetbrains.kotlin.config.LanguageVersionSettings;
 import org.jetbrains.kotlin.descriptors.*;
 import org.jetbrains.kotlin.diagnostics.DiagnosticUtilsKt;
@@ -155,7 +156,7 @@ public class DataFlowAnalyzer {
                     }
                     result.set(dataFlowInfo);
                 }
-                else  {
+                else {
                     DataFlowInfo expressionFlowInfo = facade.getTypeInfo(expression, context).getDataFlowInfo();
                     KtExpression left = expression.getLeft();
                     if (left == null) return;
@@ -177,6 +178,13 @@ public class DataFlowAnalyzer {
                     else if (operationToken == KtTokens.EXCLEQ || operationToken == KtTokens.EXCLEQEQEQ) {
                         equals = false;
                     }
+                    else if (operationToken == KtTokens.ELVIS &&
+                             languageVersionSettings.supportsFeature(LanguageFeature.BooleanElvisBoundSmartCasts) &&
+                             right instanceof KtConstantExpression &&
+                             KotlinBuiltIns.isBoolean(rhsType)) {
+                        // ?: false is equivalent to == true, ?: true is equivalent to != false
+                        equals = KtPsiUtil.isFalseConstant(right);
+                    }
                     if (equals != null) {
                         if (equals == conditionValue) { // this means: equals && conditionValue || !equals && !conditionValue
                             boolean identityEquals = operationToken == KtTokens.EQEQEQ ||

compiler/testData/diagnostics/tests/smartCasts/elvis/basicOff.kt

@@ -0,0 +1,50 @@
+// !LANGUAGE: -BooleanElvisBoundSmartCasts
+
+interface Order {
+    val expired: Boolean?
+
+    fun notExpired(): Boolean
+
+    fun doSomething()
+}
+
+fun foo(o: Any) {
+    val order = o as? Order
+    if (order?.expired ?: false) {
+        order<!UNSAFE_CALL!>.<!>doSomething()
+    }
+    else {
+
+    }
+    if (order?.notExpired() ?: false) {
+        order<!UNSAFE_CALL!>.<!>doSomething()
+    }
+}
+
+fun bar(o: Any) {
+    val order = o as? Order
+    if (order?.expired ?: true) {
+
+    }
+    else {
+        order!!.doSomething()
+    }
+    if (order?.notExpired() ?: true) {
+
+    }
+    else {
+        order!!.doSomething()
+    }
+}
+
+fun baz(o: Boolean?) {
+    if (o ?: false) {
+        o<!UNSAFE_CALL!>.<!>hashCode()
+    }
+    if (o ?: true) {
+
+    }
+    else {
+        o<!UNSAFE_CALL!>.<!>hashCode()
+    }
+}

compiler/testData/diagnostics/tests/smartCasts/elvis/basicOff.txt

@@ -0,0 +1,14 @@
+package
+
+public fun bar(/*0*/ o: kotlin.Any): kotlin.Unit
+public fun baz(/*0*/ o: kotlin.Boolean?): kotlin.Unit
+public fun foo(/*0*/ o: kotlin.Any): kotlin.Unit
+
+public interface Order {
+    public abstract val expired: kotlin.Boolean?
+    public abstract fun doSomething(): kotlin.Unit
+    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 abstract fun notExpired(): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/smartCasts/elvis/basicOn.kt

@@ -0,0 +1,50 @@
+// !LANGUAGE: +BooleanElvisBoundSmartCasts
+
+interface Order {
+    val expired: Boolean?
+
+    fun notExpired(): Boolean
+
+    fun doSomething()
+}
+
+fun foo(o: Any) {
+    val order = o as? Order
+    if (order?.expired ?: false) {
+        <!DEBUG_INFO_SMARTCAST!>order<!>.doSomething()
+    }
+    else {
+
+    }
+    if (order?.notExpired() ?: false) {
+        <!DEBUG_INFO_SMARTCAST!>order<!>.doSomething()
+    }
+}
+
+fun bar(o: Any) {
+    val order = o as? Order
+    if (order?.expired ?: true) {
+
+    }
+    else {
+        order<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.doSomething()
+    }
+    if (order?.notExpired() ?: true) {
+
+    }
+    else {
+        order<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.doSomething()
+    }
+}
+
+fun baz(o: Boolean?) {
+    if (o ?: false) {
+        <!DEBUG_INFO_SMARTCAST!>o<!>.hashCode()
+    }
+    if (o ?: true) {
+
+    }
+    else {
+        <!DEBUG_INFO_SMARTCAST!>o<!>.hashCode()
+    }
+}

compiler/testData/diagnostics/tests/smartCasts/elvis/basicOn.txt

@@ -0,0 +1,14 @@
+package
+
+public fun bar(/*0*/ o: kotlin.Any): kotlin.Unit
+public fun baz(/*0*/ o: kotlin.Boolean?): kotlin.Unit
+public fun foo(/*0*/ o: kotlin.Any): kotlin.Unit
+
+public interface Order {
+    public abstract val expired: kotlin.Boolean?
+    public abstract fun doSomething(): kotlin.Unit
+    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 abstract fun notExpired(): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/smartCasts/safecalls/safeAccessReceiverNotNull.kt

@@ -1,4 +1,4 @@
-// !LANGUAGE: -SafeCastCheckBoundSmartCasts
+// !LANGUAGE: -SafeCastCheckBoundSmartCasts -BooleanElvisBoundSmartCasts
 // A set of examples for
 // "If the result of a safe call is not null, understand that its receiver is not null"
 // and some other improvements for nullability detection

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -20299,6 +20299,27 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 }
             }
 
+            @TestMetadata("compiler/testData/diagnostics/tests/smartCasts/elvis")
+            @TestDataPath("$PROJECT_ROOT")
+            @RunWith(JUnit3RunnerWithInners.class)
+            public static class Elvis extends AbstractDiagnosticsTest {
+                public void testAllFilesPresentInElvis() throws Exception {
+                    KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/diagnostics/tests/smartCasts/elvis"), Pattern.compile("^(.+)\\.kt$"), TargetBackend.ANY, true);
+                }
+
+                @TestMetadata("basicOff.kt")
+                public void testBasicOff() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/smartCasts/elvis/basicOff.kt");
+                    doTest(fileName);
+                }
+
+                @TestMetadata("basicOn.kt")
+                public void testBasicOn() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/smartCasts/elvis/basicOn.kt");
+                    doTest(fileName);
+                }
+            }
+
             @TestMetadata("compiler/testData/diagnostics/tests/smartCasts/inference")
             @TestDataPath("$PROJECT_ROOT")
             @RunWith(JUnit3RunnerWithInners.class)

compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -55,6 +55,7 @@ enum class LanguageFeature(
     SoundSmartCastsAfterTry(KOTLIN_1_2),
     DeprecatedFieldForInvisibleCompanionObject(KOTLIN_1_2),
     SafeCastCheckBoundSmartCasts(KOTLIN_1_2),
+    BooleanElvisBoundSmartCasts(KOTLIN_1_2),
 
     // Experimental features