[FE 1.0] Check for type mismatch for empty when statements

^KT-47922 Fixed

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsTestGenerated.java

@@ -31921,6 +31921,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                 runTest("compiler/testData/diagnostics/tests/when/kt4434.kt");
             }
 
+            @Test
+            @TestMetadata("kt47922.kt")
+            public void testKt47922() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/when/kt47922.kt");
+            }
+
             @Test
             @TestMetadata("kt9929.kt")
             public void testKt9929() throws Exception {

compiler/fir/analysis-tests/tests-gen/org/jetbrains/kotlin/test/runners/FirOldFrontendDiagnosticsWithLightTreeTestGenerated.java

@@ -31921,6 +31921,12 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
                 runTest("compiler/testData/diagnostics/tests/when/kt4434.kt");
             }
 
+            @Test
+            @TestMetadata("kt47922.kt")
+            public void testKt47922() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/when/kt47922.kt");
+            }
+
             @Test
             @TestMetadata("kt9929.kt")
             public void testKt9929() throws Exception {

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

@@ -305,8 +305,11 @@ public class DataFlowAnalyzer {
         }
 
         if (expression instanceof KtWhenExpression) {
-            // No need in additional check because type mismatch is already reported for entries
-            return expressionType;
+            KtWhenExpression whenExpression = (KtWhenExpression) expression;
+            if (!whenExpression.getEntries().isEmpty()) {
+                // No need in additional check because type mismatch is already reported for entries
+                return expressionType;
+            }
         }
 
         SmartCastResult castResult = checkPossibleCast(expressionType, expression, c);

compiler/testData/diagnostics/tests/sealed/WhenOnEmptySealed.fir.kt

@@ -0,0 +1,11 @@
+// !DIAGNOSTICS: -UNUSED_EXPRESSION
+sealed class Sealed {
+
+}
+
+fun foo(s: Sealed): Int {
+    return <!NO_ELSE_IN_WHEN!>when<!>(s) {
+        // We do not return anything, so else branch must be here
+    }
+}
+

compiler/testData/diagnostics/tests/sealed/WhenOnEmptySealed.kt

@@ -1,12 +1,11 @@
-// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_EXPRESSION
 sealed class Sealed {
 
 }
 
 fun foo(s: Sealed): Int {
-    return <!NO_ELSE_IN_WHEN!>when<!>(s) {
+    return <!TYPE_MISMATCH!><!NO_ELSE_IN_WHEN!>when<!>(s) {
         // We do not return anything, so else branch must be here
-    }
+    }<!>
 }
 

compiler/testData/diagnostics/tests/when/kt47922.fir.kt

@@ -0,0 +1,21 @@
+// ISSUE: KT-47922
+
+package whencase.castissue
+
+sealed class SealedBase {
+    object Complete : SealedBase()
+}
+
+abstract class NonSealedBase {
+    object Complete : NonSealedBase()
+}
+
+sealed class ToState
+
+val sealedTest: SealedBase.() -> ToState? = {
+    <!NON_EXHAUSTIVE_WHEN_STATEMENT!>when<!>(this) {}
+}
+
+val nonSealedTest: NonSealedBase.() -> ToState? = {
+    when(this) {}
+}

compiler/testData/diagnostics/tests/when/kt47922.kt

@@ -0,0 +1,21 @@
+// ISSUE: KT-47922
+
+package whencase.castissue
+
+sealed class SealedBase {
+    object Complete : SealedBase()
+}
+
+abstract class NonSealedBase {
+    object Complete : NonSealedBase()
+}
+
+sealed class ToState
+
+val sealedTest: SealedBase.() -> ToState? = {
+    <!TYPE_MISMATCH!><!NON_EXHAUSTIVE_WHEN_STATEMENT!>when<!>(this) {}<!>
+}
+
+val nonSealedTest: NonSealedBase.() -> ToState? = {
+    <!TYPE_MISMATCH!>when(this) {}<!>
+}

compiler/testData/diagnostics/tests/when/kt47922.txt

@@ -0,0 +1,44 @@
+package
+
+package whencase {
+
+    package whencase.castissue {
+        public val nonSealedTest: whencase.castissue.NonSealedBase.() -> whencase.castissue.ToState?
+        public val sealedTest: whencase.castissue.SealedBase.() -> whencase.castissue.ToState?
+
+        public abstract class NonSealedBase {
+            public constructor NonSealedBase()
+            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 object Complete : whencase.castissue.NonSealedBase {
+                private constructor Complete()
+                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 sealed class SealedBase {
+            protected constructor SealedBase()
+            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 object Complete : whencase.castissue.SealedBase {
+                private constructor Complete()
+                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 sealed class ToState {
+            protected constructor ToState()
+            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
+        }
+    }
+}

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/DiagnosticTestGenerated.java

@@ -32017,6 +32017,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/tests/when/kt4434.kt");
             }
 
+            @Test
+            @TestMetadata("kt47922.kt")
+            public void testKt47922() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/when/kt47922.kt");
+            }
+
             @Test
             @TestMetadata("kt9929.kt")
             public void testKt9929() throws Exception {

compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/exhaustive-when-expressions/p-2/neg/1.1.fir.kt

@@ -0,0 +1,25 @@
+// SKIP_TXT
+
+/*
+ * KOTLIN DIAGNOSTICS SPEC TEST (NEGATIVE)
+ *
+ * SPEC VERSION: 0.1-100
+ * MAIN LINK: expressions, when-expression, exhaustive-when-expressions -> paragraph 2 -> sentence 1
+ * NUMBER: 1
+ * DESCRIPTION: Non-exhaustive when, without bound value, without else branch.
+ */
+
+// TESTCASE NUMBER: 1
+fun case_1(value_1: Int): String = <!NO_ELSE_IN_WHEN!>when<!> {
+    value_1 == 1 -> ""
+    value_1 == 2 -> ""
+    value_1 == 3 -> ""
+}
+
+// TESTCASE NUMBER: 2
+fun case_2(value_1: Int): String = <!NO_ELSE_IN_WHEN!>when<!> {
+    value_1 == 1 -> ""
+}
+
+// TESTCASE NUMBER: 3
+fun case_3(): Int = <!NO_ELSE_IN_WHEN!>when<!> {}

compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/exhaustive-when-expressions/p-2/neg/1.1.kt

@@ -1,4 +1,3 @@
-// FIR_IDENTICAL
 // SKIP_TXT
 
 /*
@@ -23,4 +22,4 @@ fun case_2(value_1: Int): String = <!NO_ELSE_IN_WHEN!>when<!> {
 }
 
 // TESTCASE NUMBER: 3
-fun case_3(): Int = <!NO_ELSE_IN_WHEN!>when<!> {}
+fun case_3(): Int = <!TYPE_MISMATCH!><!NO_ELSE_IN_WHEN!>when<!> {}<!>

compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/exhaustive-when-expressions/p-2/neg/1.2.fir.kt

@@ -0,0 +1,26 @@
+// !DIAGNOSTICS: -UNUSED_EXPRESSION
+// SKIP_TXT
+
+/*
+ * KOTLIN DIAGNOSTICS SPEC TEST (NEGATIVE)
+ *
+ * SPEC VERSION: 0.1-100
+ * MAIN LINK: expressions, when-expression, exhaustive-when-expressions -> paragraph 2 -> sentence 1
+ * NUMBER: 2
+ * DESCRIPTION: Non-exhaustive when, with bound value, without else branch.
+ */
+
+// TESTCASE NUMBER: 1
+fun case_1(value_1: Int): String = <!NO_ELSE_IN_WHEN!>when<!> (value_1) {
+    1 -> ""
+    2 -> ""
+    3 -> ""
+}
+
+// TESTCASE NUMBER: 2
+fun case_2(value_1: Int): String = <!NO_ELSE_IN_WHEN!>when<!> (value_1) {
+    1 -> ""
+}
+
+// TESTCASE NUMBER: 3
+fun case_3(value_1: Int): Int = <!NO_ELSE_IN_WHEN!>when<!> (value_1) {}

compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/exhaustive-when-expressions/p-2/neg/1.2.kt

@@ -1,4 +1,3 @@
-// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_EXPRESSION
 // SKIP_TXT
 
@@ -24,4 +23,4 @@ fun case_2(value_1: Int): String = <!NO_ELSE_IN_WHEN!>when<!> (value_1) {
 }
 
 // TESTCASE NUMBER: 3
-fun case_3(value_1: Int): Int = <!NO_ELSE_IN_WHEN!>when<!> (value_1) {}
+fun case_3(value_1: Int): Int = <!TYPE_MISMATCH!><!NO_ELSE_IN_WHEN!>when<!> (value_1) {}<!>

compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/exhaustive-when-expressions/p-2/neg/11.1.fir.kt

@@ -0,0 +1,35 @@
+// LANGUAGE: +ProhibitSimplificationOfNonTrivialConstBooleanExpressions
+// !DIAGNOSTICS: -UNUSED_EXPRESSION
+// SKIP_TXT
+
+/*
+ * KOTLIN DIAGNOSTICS SPEC TEST (NEGATIVE)
+ *
+ * SPEC VERSION: 0.1-435
+ * MAIN LINK: expressions, when-expression, exhaustive-when-expressions -> paragraph 2 -> sentence 11
+ * NUMBER: 1
+ * DESCRIPTION: Non-exhaustive when using nullable boolean values.
+ */
+
+
+// TESTCASE NUMBER: 1
+fun case_1(value_1: Boolean?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    true -> ""
+    false -> ""
+}
+
+// TESTCASE NUMBER: 2
+fun case_2(value_1: Boolean?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    true -> ""
+    null -> ""
+}
+
+// TESTCASE NUMBER: 3
+fun case_3(value_1: Boolean?): Int = <!NO_ELSE_IN_WHEN!>when<!>(value_1) { }
+
+// TESTCASE NUMBER: 4
+fun case_4(value_1: Boolean?): String = <!NO_ELSE_IN_WHEN!>when<!> (value_1) {
+    true && false && ((true || false)) || true && !!!false && !!!true -> ""
+    true && false && ((true || false)) || true && !!!false -> ""
+    null -> ""
+}

compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/exhaustive-when-expressions/p-2/neg/11.1.kt

@@ -1,4 +1,3 @@
-// FIR_IDENTICAL
 // LANGUAGE: +ProhibitSimplificationOfNonTrivialConstBooleanExpressions
 // !DIAGNOSTICS: -UNUSED_EXPRESSION
 // SKIP_TXT
@@ -26,7 +25,7 @@ fun case_2(value_1: Boolean?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
 }
 
 // TESTCASE NUMBER: 3
-fun case_3(value_1: Boolean?): Int = <!NO_ELSE_IN_WHEN!>when<!>(value_1) { }
+fun case_3(value_1: Boolean?): Int = <!TYPE_MISMATCH!><!NO_ELSE_IN_WHEN!>when<!>(value_1) { }<!>
 
 // TESTCASE NUMBER: 4
 fun case_4(value_1: Boolean?): String = <!NO_ELSE_IN_WHEN!>when<!> (value_1) {

compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/exhaustive-when-expressions/p-2/neg/11.2.fir.kt

@@ -0,0 +1,81 @@
+// !DIAGNOSTICS: -UNUSED_EXPRESSION
+// SKIP_TXT
+
+/*
+ * KOTLIN DIAGNOSTICS SPEC TEST (NEGATIVE)
+ *
+ * SPEC VERSION: 0.1-435
+ * MAIN LINK: expressions, when-expression, exhaustive-when-expressions -> paragraph 2 -> sentence 11
+ * NUMBER: 2
+ * DESCRIPTION: Non-exhaustive when using subclasses of the nullable sealed class.
+ * HELPERS: sealedClasses
+ */
+
+// TESTCASE NUMBER: 1
+fun case_1(value_1: SealedClass?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    is SealedChild1 -> ""
+    is SealedChild2 -> ""
+    is SealedChild3 -> ""
+}
+
+// TESTCASE NUMBER: 2
+fun case_2(value_1: SealedClassMixed?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    is SealedMixedChild1 -> ""
+    is SealedMixedChild2 -> ""
+    SealedMixedChildObject1 -> ""
+    null -> ""
+}
+
+// TESTCASE NUMBER: 3
+fun case_3(value_1: SealedClassMixed?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    null, is SealedMixedChild1, is SealedMixedChild2, SealedMixedChildObject1 -> ""
+}
+
+// TESTCASE NUMBER: 4
+fun case_4(value_1: SealedClassMixed?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    is SealedMixedChild1 -> ""
+    is SealedMixedChild2 -> ""
+    is SealedMixedChild3 -> ""
+    SealedMixedChildObject1 -> ""
+    SealedMixedChildObject2 -> ""
+    SealedMixedChildObject3 -> ""
+}
+
+// TESTCASE NUMBER: 5
+fun case_5(value_1: SealedClassMixed?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    is SealedMixedChild1 -> ""
+    is SealedMixedChild2 -> ""
+    is SealedMixedChild3 -> ""
+}
+
+// TESTCASE NUMBER: 6
+fun case_6(value_1: SealedClassMixed?): Int = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {}
+
+// TESTCASE NUMBER: 7
+fun case_7(value_1: SealedClassMixed?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    is SealedMixedChild1 -> ""
+    is SealedMixedChild2-> ""
+    is SealedMixedChild3 -> ""
+    null -> ""
+}
+
+// TESTCASE NUMBER: 8
+fun case_8(value_1: SealedClassMixed?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    SealedMixedChildObject1 -> ""
+}
+
+/*
+ * TESTCASE NUMBER: 9
+ * DISCUSSION: maybe make exhaustive without else?
+ */
+fun case_9(value_1: Any?): String = <!NO_ELSE_IN_WHEN!>when<!> (value_1) {
+    is Any -> ""
+    null -> ""
+}
+
+/*
+ * TESTCASE NUMBER: 10
+ * DISCUSSION
+ * ISSUES: KT-26044
+ */
+fun case_10(value: SealedClassEmpty): String = <!NO_ELSE_IN_WHEN!>when<!> (value) {}

compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/exhaustive-when-expressions/p-2/neg/11.2.kt

@@ -1,4 +1,3 @@
-// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_EXPRESSION
 // SKIP_TXT
 
@@ -50,7 +49,7 @@ fun case_5(value_1: SealedClassMixed?): String = <!NO_ELSE_IN_WHEN!>when<!>(valu
 }
 
 // TESTCASE NUMBER: 6
-fun case_6(value_1: SealedClassMixed?): Int = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {}
+fun case_6(value_1: SealedClassMixed?): Int = <!TYPE_MISMATCH!><!NO_ELSE_IN_WHEN!>when<!>(value_1) {}<!>
 
 // TESTCASE NUMBER: 7
 fun case_7(value_1: SealedClassMixed?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
@@ -79,4 +78,4 @@ fun case_9(value_1: Any?): String = <!NO_ELSE_IN_WHEN!>when<!> (value_1) {
  * DISCUSSION
  * ISSUES: KT-26044
  */
-fun case_10(value: SealedClassEmpty): String = <!NO_ELSE_IN_WHEN!>when<!> (value) {}
+fun case_10(value: SealedClassEmpty): String = <!TYPE_MISMATCH!><!NO_ELSE_IN_WHEN!>when<!> (value) {}<!>

compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/exhaustive-when-expressions/p-2/neg/11.3.fir.kt

@@ -0,0 +1,46 @@
+// !DIAGNOSTICS: -UNUSED_EXPRESSION
+// SKIP_TXT
+
+/*
+ * KOTLIN DIAGNOSTICS SPEC TEST (NEGATIVE)
+ *
+ * SPEC VERSION: 0.1-435
+ * MAIN LINK: expressions, when-expression, exhaustive-when-expressions -> paragraph 2 -> sentence 11
+ * NUMBER: 3
+ * DESCRIPTION: Non-exhaustive when using nullable enum values.
+ * HELPERS: enumClasses
+ */
+
+// TESTCASE NUMBER: 1
+fun case_1(value_1: EnumClass?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    EnumClass.EAST -> ""
+    EnumClass.SOUTH -> ""
+    EnumClass.NORTH -> ""
+    EnumClass.WEST -> ""
+}
+
+// TESTCASE NUMBER: 2
+fun case_2(value_1: EnumClass?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    EnumClass.EAST -> ""
+    EnumClass.SOUTH -> ""
+    EnumClass.NORTH -> ""
+    null -> ""
+}
+
+// TESTCASE NUMBER: 3
+fun case_3(value_1: EnumClass?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    EnumClass.EAST, null, EnumClass.SOUTH, EnumClass.NORTH -> ""
+}
+
+// TESTCASE NUMBER: 4
+fun case_4(value_1: EnumClassSingle): Int = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {}
+
+// TESTCASE NUMBER: 5
+fun case_5(value_1: EnumClassSingle?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    EnumClassSingle.EVERYTHING -> ""
+}
+
+// TESTCASE NUMBER: 6
+fun case_6(value_1: EnumClassSingle?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    null -> ""
+}

compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/exhaustive-when-expressions/p-2/neg/11.3.kt

@@ -1,4 +1,3 @@
-// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_EXPRESSION
 // SKIP_TXT
 
@@ -34,7 +33,7 @@ fun case_3(value_1: EnumClass?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
 }
 
 // TESTCASE NUMBER: 4
-fun case_4(value_1: EnumClassSingle): Int = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {}
+fun case_4(value_1: EnumClassSingle): Int = <!TYPE_MISMATCH!><!NO_ELSE_IN_WHEN!>when<!>(value_1) {}<!>
 
 // TESTCASE NUMBER: 5
 fun case_5(value_1: EnumClassSingle?): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {

compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/exhaustive-when-expressions/p-2/neg/3.1.fir.kt

@@ -0,0 +1,53 @@
+// LANGUAGE: +ProhibitSimplificationOfNonTrivialConstBooleanExpressions
+// !DIAGNOSTICS: -UNUSED_EXPRESSION
+// SKIP_TXT
+
+/*
+ * KOTLIN DIAGNOSTICS SPEC TEST (NEGATIVE)
+ *
+ * SPEC VERSION: 0.1-100
+ * MAIN LINK: expressions, when-expression, exhaustive-when-expressions -> paragraph 2 -> sentence 3
+ * NUMBER: 1
+ * DESCRIPTION: Non-exhaustive when using boolean values.
+ */
+
+// TESTCASE NUMBER: 1
+fun case_1(value_1: Boolean): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    true -> ""
+}
+
+// TESTCASE NUMBER: 2
+fun case_2(value_1: Boolean): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    false -> ""
+}
+
+// TESTCASE NUMBER: 3
+fun case_3(value_1: Boolean): Int = <!NO_ELSE_IN_WHEN!>when<!>(value_1) { }
+
+// TESTCASE NUMBER: 4
+fun case_4(value_1: Boolean): String = <!NO_ELSE_IN_WHEN!>when<!> {
+    value_1 == true -> ""
+    value_1 == false -> ""
+}
+
+/*
+ * TESTCASE NUMBER: 5
+ * DISCUSSION: maybe use const propagation here?
+ * ISSUES: KT-25265
+ */
+fun case_5(value_1: Boolean): String {
+    val trueValue = true
+    val falseValue = false
+
+    return <!NO_ELSE_IN_WHEN!>when<!> (value_1) {
+        trueValue -> ""
+        falseValue -> ""
+    }
+}
+
+
+// TESTCASE NUMBER: 6
+fun case_6(value_1: Boolean): String = <!NO_ELSE_IN_WHEN!>when<!> (value_1) {
+    true && false && ((true || false)) || true && !!!false && !!!true -> ""
+    true && false && ((true || false)) || true && !!!false -> ""
+}

compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/exhaustive-when-expressions/p-2/neg/3.1.kt

@@ -1,4 +1,3 @@
-// FIR_IDENTICAL
 // LANGUAGE: +ProhibitSimplificationOfNonTrivialConstBooleanExpressions
 // !DIAGNOSTICS: -UNUSED_EXPRESSION
 // SKIP_TXT
@@ -23,7 +22,7 @@ fun case_2(value_1: Boolean): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
 }
 
 // TESTCASE NUMBER: 3
-fun case_3(value_1: Boolean): Int = <!NO_ELSE_IN_WHEN!>when<!>(value_1) { }
+fun case_3(value_1: Boolean): Int = <!TYPE_MISMATCH!><!NO_ELSE_IN_WHEN!>when<!>(value_1) { }<!>
 
 // TESTCASE NUMBER: 4
 fun case_4(value_1: Boolean): String = <!NO_ELSE_IN_WHEN!>when<!> {

compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/exhaustive-when-expressions/p-2/neg/9.1.fir.kt

@@ -0,0 +1,83 @@
+// !DIAGNOSTICS: -UNUSED_EXPRESSION
+// SKIP_TXT
+
+/*
+ * KOTLIN DIAGNOSTICS SPEC TEST (NEGATIVE)
+ *
+ * SPEC VERSION: 0.1-435
+ * MAIN LINK: expressions, when-expression, exhaustive-when-expressions -> paragraph 2 -> sentence 9
+ * NUMBER: 1
+ * DESCRIPTION: Non-exhaustive when using subclasses of the sealed class.
+ * HELPERS: sealedClasses
+ */
+
+// TESTCASE NUMBER: 1
+fun case_1(value_1: SealedClass): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    is SealedChild1 -> ""
+    is SealedChild2 -> ""
+}
+
+// TESTCASE NUMBER: 2
+fun case_2(value_1: SealedClass): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    is SealedChild1, is SealedChild2 -> ""
+}
+
+// TESTCASE NUMBER: 3
+fun case_3(value_1: SealedClassMixed): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    is SealedMixedChild1 -> ""
+    is SealedMixedChild2 -> ""
+    SealedMixedChildObject1 -> ""
+}
+
+// TESTCASE NUMBER: 4
+fun case_4(value_1: SealedClassMixed): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    SealedMixedChildObject1, is SealedMixedChild2, is SealedMixedChild1 -> ""
+}
+
+// TESTCASE NUMBER: 5
+fun case_5(value_1: SealedClassMixed): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    is SealedMixedChild1 -> ""
+    is SealedMixedChild2 -> ""
+    is SealedMixedChild3 -> ""
+}
+
+// TESTCASE NUMBER: 6
+fun case_6(value_1: SealedClassMixed): Int = <!NO_ELSE_IN_WHEN!>when<!>(value_1) { }
+
+// TESTCASE NUMBER: 7
+fun case_7(value_1: SealedClassSingleWithObject): Int = <!NO_ELSE_IN_WHEN!>when<!>(value_1) { }
+
+// TESTCASE NUMBER: 8
+fun case_8(value_1: SealedClassEmpty): String = <!NO_ELSE_IN_WHEN!>when<!> (value_1) { }
+
+// TESTCASE NUMBER: 9
+fun case_9(value_1: Number): String = <!NO_ELSE_IN_WHEN!>when<!> (value_1) {
+    is Byte -> ""
+    is Double -> ""
+    is Float -> ""
+    is Int -> ""
+    is Long -> ""
+    is Short -> ""
+}
+
+/*
+ * TESTCASE NUMBER: 10
+ * DISCUSSION: maybe make exhaustive without else?
+ */
+fun case_10(value_1: Any): String = <!NO_ELSE_IN_WHEN!>when<!> (value_1) {
+    <!USELESS_IS_CHECK!>is Any<!> -> ""
+}
+
+// TESTCASE NUMBER: 11
+fun case_11(value_1: SealedClass): String = <!NO_ELSE_IN_WHEN!>when<!> {
+    value_1 is SealedChild1 -> ""
+    value_1 is SealedChild2 -> ""
+    value_1 is SealedChild3 -> ""
+}
+
+// TESTCASE NUMBER: 12
+fun case_12(value_1: SealedClassMixed): String = <!NO_ELSE_IN_WHEN!>when<!>(value_1) {
+    is SealedMixedChild1 -> ""
+    is SealedMixedChild2 -> ""
+    is SealedMixedChild3 -> ""
+}

compiler/tests-spec/testData/diagnostics/linked/expressions/when-expression/exhaustive-when-expressions/p-2/neg/9.1.kt

@@ -1,4 +1,3 @@
-// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_EXPRESSION
 // SKIP_TXT
 
@@ -43,13 +42,13 @@ fun case_5(value_1: SealedClassMixed): String = <!NO_ELSE_IN_WHEN!>when<!>(value
 }
 
 // TESTCASE NUMBER: 6
-fun case_6(value_1: SealedClassMixed): Int = <!NO_ELSE_IN_WHEN!>when<!>(value_1) { }
+fun case_6(value_1: SealedClassMixed): Int = <!TYPE_MISMATCH!><!NO_ELSE_IN_WHEN!>when<!>(value_1) { }<!>
 
 // TESTCASE NUMBER: 7
-fun case_7(value_1: SealedClassSingleWithObject): Int = <!NO_ELSE_IN_WHEN!>when<!>(value_1) { }
+fun case_7(value_1: SealedClassSingleWithObject): Int = <!TYPE_MISMATCH!><!NO_ELSE_IN_WHEN!>when<!>(value_1) { }<!>
 
 // TESTCASE NUMBER: 8
-fun case_8(value_1: SealedClassEmpty): String = <!NO_ELSE_IN_WHEN!>when<!> (value_1) { }
+fun case_8(value_1: SealedClassEmpty): String = <!TYPE_MISMATCH!><!NO_ELSE_IN_WHEN!>when<!> (value_1) { }<!>
 
 // TESTCASE NUMBER: 9
 fun case_9(value_1: Number): String = <!NO_ELSE_IN_WHEN!>when<!> (value_1) {

idea/idea-frontend-fir/idea-fir-low-level-api/tests/org/jetbrains/kotlin/idea/fir/low/level/api/diagnostic/compiler/based/DiagnosisCompilerTestFE10TestdataTestGenerated.java

@@ -31921,6 +31921,12 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                 runTest("compiler/testData/diagnostics/tests/when/kt4434.kt");
             }
 
+            @Test
+            @TestMetadata("kt47922.kt")
+            public void testKt47922() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/when/kt47922.kt");
+            }
+
             @Test
             @TestMetadata("kt9929.kt")
             public void testKt9929() throws Exception {