FIR: Preserve K1 behavior for rawTypeValue ?: nothingTypedValue

It's been approximated to the non-raw version back then

^KT-54526 Fixed

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

@@ -24181,6 +24181,12 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                     runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/kt47459.kt");
                 }
 
+                @Test
+                @TestMetadata("lostRawTypeAfterElvis.kt")
+                public void testLostRawTypeAfterElvis() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/lostRawTypeAfterElvis.kt");
+                }
+
                 @Test
                 @TestMetadata("noTypeArgumentsForRawScopedMembers.kt")
                 public void testNoTypeArgumentsForRawScopedMembers() throws Exception {

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

@@ -24181,6 +24181,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                     runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/kt47459.kt");
                 }
 
+                @Test
+                @TestMetadata("lostRawTypeAfterElvis.kt")
+                public void testLostRawTypeAfterElvis() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/lostRawTypeAfterElvis.kt");
+                }
+
                 @Test
                 @TestMetadata("noTypeArgumentsForRawScopedMembers.kt")
                 public void testNoTypeArgumentsForRawScopedMembers() throws Exception {

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

@@ -24181,6 +24181,12 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
                     runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/kt47459.kt");
                 }
 
+                @Test
+                @TestMetadata("lostRawTypeAfterElvis.kt")
+                public void testLostRawTypeAfterElvis() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/lostRawTypeAfterElvis.kt");
+                }
+
                 @Test
                 @TestMetadata("noTypeArgumentsForRawScopedMembers.kt")
                 public void testNoTypeArgumentsForRawScopedMembers() throws Exception {

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/body/resolve/FirControlFlowStatementsResolveTransformer.kt

@@ -249,7 +249,10 @@ class FirControlFlowStatementsResolveTransformer(transformer: FirBodyResolveTran
         if (result.rhs.typeRef.coneTypeSafe<ConeKotlinType>()?.isNothing == true) {
             val lhsType = result.lhs.typeRef.coneTypeSafe<ConeKotlinType>()
             if (lhsType != null) {
-                val newReturnType = lhsType.makeConeTypeDefinitelyNotNullOrNotNull(session.typeContext)
+                // Converting to non-raw type is necessary to preserver the K1 semantics (see KT-54526)
+                val newReturnType =
+                    lhsType.makeConeTypeDefinitelyNotNullOrNotNull(session.typeContext)
+                        .convertToNonRawVersion()
                 result.replaceTypeRef(result.typeRef.resolvedTypeFromPrototype(newReturnType))
                 isLhsNotNull = true
             }

compiler/testData/diagnostics/tests/platformTypes/rawTypes/lostRawTypeAfterElvis.kt

@@ -0,0 +1,22 @@
+// SKIP_TXT
+// FIR_IDENTICAL
+// FILE: Generic.java
+public class Generic<T> {
+    public static class ML<E> {}
+    public static Generic create() { return null; }
+    public <E> E foo(ML<E> w) { }
+}
+
+// FILE: main.kt
+import Generic.ML
+
+fun main(w: ML<String>) {
+    val generic2 = Generic.create() ?: return
+
+    // Not enough information to infer E (both K1 and K2 after KT-41794 is done)
+    // Because generic information is erased from the raw type scope of `generic1`
+    // But the parameter E is still there (that is a questionable behavior)
+
+    // `generic2` does have just non-raw type `Generic<Any!>..Generic<*>?`
+    generic2.foo(w).length // OK in K1, fails in K2 after KT-41794 is done
+}

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

@@ -24187,6 +24187,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                     runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/kt47459.kt");
                 }
 
+                @Test
+                @TestMetadata("lostRawTypeAfterElvis.kt")
+                public void testLostRawTypeAfterElvis() throws Exception {
+                    runTest("compiler/testData/diagnostics/tests/platformTypes/rawTypes/lostRawTypeAfterElvis.kt");
+                }
+
                 @Test
                 @TestMetadata("noTypeArgumentsForRawScopedMembers.kt")
                 public void testNoTypeArgumentsForRawScopedMembers() throws Exception {