Mark Unit unspillable if it is merged with unspillable Unit

#KT-42004: Fixed

compiler/backend/src/org/jetbrains/kotlin/codegen/coroutines/RedundantLocalsEliminationMethodTransformer.kt

@@ -136,7 +136,11 @@ private class UnitSourceInterpreter(private val localVariables: Set<Int>) : Basi
 
     override fun merge(value1: BasicValue?, value2: BasicValue?): BasicValue? =
         if (value1 is UnitValue && value2 is UnitValue) {
-            UnitValue(value1.insns.union(value2.insns))
+            val newValue = UnitValue(value1.insns.union(value2.insns))
+            if (newValue.insns.any { it in unspillableUnitValues }) {
+                markUnspillable(newValue)
+            }
+            newValue
         } else {
             // Mark unit values as unspillable if we merge them with non-unit values here.
             // This is conservative since the value could turn out to be unused.

compiler/fir/fir2ir/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java

@@ -8997,6 +8997,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             public void testRefinedIntTypesAnalysis() throws Exception {
                 runTest("compiler/testData/codegen/box/coroutines/varSpilling/refinedIntTypesAnalysis.kt");
             }
+
+            @TestMetadata("safeCallElvis.kt")
+            public void testSafeCallElvis() throws Exception {
+                runTest("compiler/testData/codegen/box/coroutines/varSpilling/safeCallElvis.kt");
+            }
         }
     }
 

compiler/testData/codegen/box/coroutines/varSpilling/safeCallElvis.kt

@@ -0,0 +1,32 @@
+// WITH_RUNTIME
+
+import kotlin.coroutines.*
+
+var res: String = "FAIL"
+
+class Log {
+    fun error(message: Any?) {
+        res = message as String
+    }
+}
+
+private val log = Log()
+
+class C {
+    fun method() {}
+}
+
+fun <T : Any> df(t: T, r: suspend (T) -> Unit) {
+    r.startCoroutine(t, Continuation(EmptyCoroutineContext) {})
+}
+
+fun foo(s: String, c: C?) {
+    df(s) {
+        c?.method() ?: log.error(it)
+    }
+}
+
+fun box(): String {
+    foo("OK", null)
+    return res
+}

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -10392,6 +10392,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             public void testRefinedIntTypesAnalysis() throws Exception {
                 runTest("compiler/testData/codegen/box/coroutines/varSpilling/refinedIntTypesAnalysis.kt");
             }
+
+            @TestMetadata("safeCallElvis.kt")
+            public void testSafeCallElvis() throws Exception {
+                runTest("compiler/testData/codegen/box/coroutines/varSpilling/safeCallElvis.kt");
+            }
         }
     }
 

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -10392,6 +10392,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             public void testRefinedIntTypesAnalysis() throws Exception {
                 runTest("compiler/testData/codegen/box/coroutines/varSpilling/refinedIntTypesAnalysis.kt");
             }
+
+            @TestMetadata("safeCallElvis.kt")
+            public void testSafeCallElvis() throws Exception {
+                runTest("compiler/testData/codegen/box/coroutines/varSpilling/safeCallElvis.kt");
+            }
         }
     }
 

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -8997,6 +8997,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             public void testRefinedIntTypesAnalysis() throws Exception {
                 runTest("compiler/testData/codegen/box/coroutines/varSpilling/refinedIntTypesAnalysis.kt");
             }
+
+            @TestMetadata("safeCallElvis.kt")
+            public void testSafeCallElvis() throws Exception {
+                runTest("compiler/testData/codegen/box/coroutines/varSpilling/safeCallElvis.kt");
+            }
         }
     }
 

js/js.tests/test/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java

@@ -7622,6 +7622,11 @@ public class IrJsCodegenBoxES6TestGenerated extends AbstractIrJsCodegenBoxES6Tes
             public void testRefinedIntTypesAnalysis() throws Exception {
                 runTest("compiler/testData/codegen/box/coroutines/varSpilling/refinedIntTypesAnalysis.kt");
             }
+
+            @TestMetadata("safeCallElvis.kt")
+            public void testSafeCallElvis() throws Exception {
+                runTest("compiler/testData/codegen/box/coroutines/varSpilling/safeCallElvis.kt");
+            }
         }
     }
 

js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java

@@ -7622,6 +7622,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             public void testRefinedIntTypesAnalysis() throws Exception {
                 runTest("compiler/testData/codegen/box/coroutines/varSpilling/refinedIntTypesAnalysis.kt");
             }
+
+            @TestMetadata("safeCallElvis.kt")
+            public void testSafeCallElvis() throws Exception {
+                runTest("compiler/testData/codegen/box/coroutines/varSpilling/safeCallElvis.kt");
+            }
         }
     }
 

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -7622,6 +7622,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             public void testRefinedIntTypesAnalysis() throws Exception {
                 runTest("compiler/testData/codegen/box/coroutines/varSpilling/refinedIntTypesAnalysis.kt");
             }
+
+            @TestMetadata("safeCallElvis.kt")
+            public void testSafeCallElvis() throws Exception {
+                runTest("compiler/testData/codegen/box/coroutines/varSpilling/safeCallElvis.kt");
+            }
         }
     }
 
@@ -21419,6 +21424,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                     runTest("compiler/testData/codegen/box/ranges/unsigned/expression/emptyRange.kt");
                 }
 
+                @TestMetadata("inexactDownToMinValue.kt")
+                public void testInexactDownToMinValue() throws Exception {
+                    runTest("compiler/testData/codegen/box/ranges/unsigned/expression/inexactDownToMinValue.kt");
+                }
+
                 @TestMetadata("inexactSteppedDownTo.kt")
                 public void testInexactSteppedDownTo() throws Exception {
                     runTest("compiler/testData/codegen/box/ranges/unsigned/expression/inexactSteppedDownTo.kt");
@@ -21464,11 +21474,21 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                     runTest("compiler/testData/codegen/box/ranges/unsigned/expression/openRange.kt");
                 }
 
+                @TestMetadata("overflowZeroDownToMaxValue.kt")
+                public void testOverflowZeroDownToMaxValue() throws Exception {
+                    runTest("compiler/testData/codegen/box/ranges/unsigned/expression/overflowZeroDownToMaxValue.kt");
+                }
+
                 @TestMetadata("overflowZeroToMinValue.kt")
                 public void testOverflowZeroToMinValue() throws Exception {
                     runTest("compiler/testData/codegen/box/ranges/unsigned/expression/overflowZeroToMinValue.kt");
                 }
 
+                @TestMetadata("progressionDownToMinValue.kt")
+                public void testProgressionDownToMinValue() throws Exception {
+                    runTest("compiler/testData/codegen/box/ranges/unsigned/expression/progressionDownToMinValue.kt");
+                }
+
                 @TestMetadata("progressionMaxValueMinusTwoToMaxValue.kt")
                 public void testProgressionMaxValueMinusTwoToMaxValue() throws Exception {
                     runTest("compiler/testData/codegen/box/ranges/unsigned/expression/progressionMaxValueMinusTwoToMaxValue.kt");