[FIR] Fix exception in Java scope caused by inherited member with implicit return type

It's caused by checking the return type of an inherited property.
toConeKotlinTypeProbablyFlexible() returns an error type when the
type ref is unresolved instead of throwing.
This "breaks" some override checks and in the added test, it leads
to an additional candidate being created for a synthetic property.
However, the candidate has applicability K2_SYNTHETIC_RESOLVED
and gets filtered out because the real property has a higher
applicability.

#KT-66392 Fixed

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/DiagnosticCompilerTestFE10TestdataTestGenerated.java

@@ -21984,6 +21984,12 @@ public class DiagnosticCompilerTestFE10TestdataTestGenerated extends AbstractDia
         runTest("compiler/testData/diagnostics/tests/j+k/kjkRawTypeWithKotlinUpperBound.kt");
       }
 
+      @Test
+      @TestMetadata("kjkimplicitTypesCrash.kt")
+      public void testKjkimplicitTypesCrash() {
+        runTest("compiler/testData/diagnostics/tests/j+k/kjkimplicitTypesCrash.kt");
+      }
+
       @Test
       @TestMetadata("kt1402.kt")
       public void testKt1402() {

analysis/low-level-api-fir/tests/org/jetbrains/kotlin/analysis/low/level/api/fir/diagnostic/compiler/based/LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated.java

@@ -21984,6 +21984,12 @@ public class LLFirPreresolvedReversedDiagnosticCompilerFE10TestDataTestGenerated
         runTest("compiler/testData/diagnostics/tests/j+k/kjkRawTypeWithKotlinUpperBound.kt");
       }
 
+      @Test
+      @TestMetadata("kjkimplicitTypesCrash.kt")
+      public void testKjkimplicitTypesCrash() {
+        runTest("compiler/testData/diagnostics/tests/j+k/kjkimplicitTypesCrash.kt");
+      }
+
       @Test
       @TestMetadata("kt1402.kt")
       public void testKt1402() {

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

@@ -21978,6 +21978,12 @@ public class FirLightTreeOldFrontendDiagnosticsTestGenerated extends AbstractFir
         runTest("compiler/testData/diagnostics/tests/j+k/kjkRawTypeWithKotlinUpperBound.kt");
       }
 
+      @Test
+      @TestMetadata("kjkimplicitTypesCrash.kt")
+      public void testKjkimplicitTypesCrash() {
+        runTest("compiler/testData/diagnostics/tests/j+k/kjkimplicitTypesCrash.kt");
+      }
+
       @Test
       @TestMetadata("kt1402.kt")
       public void testKt1402() {

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

@@ -21984,6 +21984,12 @@ public class FirPsiOldFrontendDiagnosticsTestGenerated extends AbstractFirPsiDia
         runTest("compiler/testData/diagnostics/tests/j+k/kjkRawTypeWithKotlinUpperBound.kt");
       }
 
+      @Test
+      @TestMetadata("kjkimplicitTypesCrash.kt")
+      public void testKjkimplicitTypesCrash() {
+        runTest("compiler/testData/diagnostics/tests/j+k/kjkimplicitTypesCrash.kt");
+      }
+
       @Test
       @TestMetadata("kt1402.kt")
       public void testKt1402() {

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/scopes/JavaClassUseSiteMemberScope.kt

@@ -18,6 +18,8 @@ import org.jetbrains.kotlin.fir.declarations.impl.FirDefaultPropertySetter
 import org.jetbrains.kotlin.fir.declarations.synthetic.FirSyntheticProperty
 import org.jetbrains.kotlin.fir.declarations.synthetic.buildSyntheticProperty
 import org.jetbrains.kotlin.fir.declarations.utils.*
+import org.jetbrains.kotlin.fir.diagnostics.ConeSimpleDiagnostic
+import org.jetbrains.kotlin.fir.diagnostics.DiagnosticKind
 import org.jetbrains.kotlin.fir.java.SyntheticPropertiesCacheKey
 import org.jetbrains.kotlin.fir.java.declarations.FirJavaClass
 import org.jetbrains.kotlin.fir.java.declarations.FirJavaMethod
@@ -890,10 +892,7 @@ class JavaClassUseSiteMemberScope(
     }
 
     private fun FirTypeRef.probablyJavaTypeRefToConeType(): ConeKotlinType {
-        return when (this) {
+        return toConeKotlinTypeProbablyFlexible(session, typeParameterStack)
-            is FirJavaTypeRef -> toConeKotlinTypeProbablyFlexible(session, typeParameterStack)
-            else -> coneType
-        }
     }
 
     // It's either overrides Collection.contains(Object) or Collection.containsAll(Collection<?>) or similar methods

compiler/testData/diagnostics/tests/j+k/kjkImplicitReturnType.kt

@@ -1,7 +1,5 @@
 // FIR_IDENTICAL
 // ISSUE: KT-66048
-// IGNORE_REVERSED_RESOLVE
-// ^KT-66392
 
 // FILE: Java1.java
 public class Java1 extends KotlinClass  {

compiler/testData/diagnostics/tests/j+k/kjkimplicitTypesCrash.fir.kt

@@ -0,0 +1,18 @@
+// ISSUE: KT-66392
+// FILE: Java1.java
+public class Java1 extends KotlinClass  {
+    @Override
+    public String getE() {
+        return "2";
+    }
+}
+
+// FILE: test.kt
+// The order of Kotlin classes is important
+class B : Java1() {
+    override var e = super.e
+}
+
+open class KotlinClass {
+    open var e = "1"
+}

compiler/testData/diagnostics/tests/j+k/kjkimplicitTypesCrash.kt

@@ -0,0 +1,18 @@
+// ISSUE: KT-66392
+// FILE: Java1.java
+public class Java1 extends KotlinClass  {
+    @Override
+    public String getE() {
+        return "2";
+    }
+}
+
+// FILE: test.kt
+// The order of Kotlin classes is important
+class B : Java1() {
+    <!ACCIDENTAL_OVERRIDE!>override var e<!> = super.e
+}
+
+open class KotlinClass {
+    open var e = "1"
+}

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

@@ -21984,6 +21984,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
         runTest("compiler/testData/diagnostics/tests/j+k/kjkRawTypeWithKotlinUpperBound.kt");
       }
 
+      @Test
+      @TestMetadata("kjkimplicitTypesCrash.kt")
+      public void testKjkimplicitTypesCrash() {
+        runTest("compiler/testData/diagnostics/tests/j+k/kjkimplicitTypesCrash.kt");
+      }
+
       @Test
       @TestMetadata("kt1402.kt")
       public void testKt1402() {