Continue processing not builder inference stub variables in the type checker during computing common super type

^KT-47148 Fixed

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

@@ -28177,6 +28177,12 @@ public class FirOldFrontendDiagnosticsTestGenerated extends AbstractFirDiagnosti
                 runTest("compiler/testData/diagnostics/tests/subtyping/kt3159.kt");
             }
 
+            @Test
+            @TestMetadata("kt47148.kt")
+            public void testKt47148() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/subtyping/kt47148.kt");
+            }
+
             @Test
             @TestMetadata("kt-1457.kt")
             public void testKt_1457() throws Exception {

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

@@ -28177,6 +28177,12 @@ public class FirOldFrontendDiagnosticsWithLightTreeTestGenerated extends Abstrac
                 runTest("compiler/testData/diagnostics/tests/subtyping/kt3159.kt");
             }
 
+            @Test
+            @TestMetadata("kt47148.kt")
+            public void testKt47148() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/subtyping/kt47148.kt");
+            }
+
             @Test
             @TestMetadata("kt-1457.kt")
             public void testKt_1457() throws Exception {

compiler/resolution.common/src/org/jetbrains/kotlin/resolve/calls/NewCommonSuperTypeCalculator.kt

@@ -175,7 +175,7 @@ object NewCommonSuperTypeCalculator {
             "There should be at least one non-stub type to compute common supertype but there are: $types"
         }
 
-        val nonStubTypeVariables = types.filter { !it.isStubType() }
+        val nonStubTypeVariables = types.filter { !it.isStubTypeForBuilderInference() }
         val areAllNonStubTypesNothing = nonStubTypeVariables.isNotEmpty() && nonStubTypeVariables.all { it.isNothing() }
         if (nonStubTypeVariables.size == 1 && !areAllNonStubTypesNothing) return nonStubTypeVariables.single()
 

compiler/testData/diagnostics/tests/subtyping/kt47148.fir.kt

@@ -0,0 +1,10 @@
+// WITH_RUNTIME
+
+interface Visitor<T> {
+    fun visit(key: String): T
+}
+val str1: String? = null
+val str2: String? = null
+fun <T> visit(arg: Visitor<T>): T = str1?.let { return@visit arg.visit(it) }
+    ?: str2?.let { return@visit arg.visit(it) }
+    ?: error("error")

compiler/testData/diagnostics/tests/subtyping/kt47148.kt

@@ -0,0 +1,10 @@
+// WITH_RUNTIME
+
+interface Visitor<T> {
+    fun visit(key: String): T
+}
+val str1: String? = null
+val str2: String? = null
+fun <T> visit(arg: Visitor<T>): T = str1?.<!IMPLICIT_NOTHING_TYPE_ARGUMENT_AGAINST_NOT_NOTHING_EXPECTED_TYPE!>let<!> { return@visit arg.visit(it) }
+    ?: str2?.<!IMPLICIT_NOTHING_TYPE_ARGUMENT_AGAINST_NOT_NOTHING_EXPECTED_TYPE!>let<!> { return@visit arg.visit(it) }
+    ?: error("error")

compiler/testData/diagnostics/tests/subtyping/kt47148.txt

@@ -0,0 +1,12 @@
+package
+
+public val str1: kotlin.String? = null
+public val str2: kotlin.String? = null
+public fun </*0*/ T> visit(/*0*/ arg: Visitor<T>): T
+
+public interface Visitor</*0*/ T> {
+    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 abstract fun visit(/*0*/ key: kotlin.String): T
+}

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

@@ -28273,6 +28273,12 @@ public class DiagnosticTestGenerated extends AbstractDiagnosticTest {
                 runTest("compiler/testData/diagnostics/tests/subtyping/kt3159.kt");
             }
 
+            @Test
+            @TestMetadata("kt47148.kt")
+            public void testKt47148() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/subtyping/kt47148.kt");
+            }
+
             @Test
             @TestMetadata("kt-1457.kt")
             public void testKt_1457() throws Exception {

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

@@ -24638,6 +24638,11 @@ public class DiagnosisCompilerTestFE10TestdataTestGenerated extends AbstractDiag
                 runTest("compiler/testData/diagnostics/tests/subtyping/kt3159.kt");
             }
 
+            @TestMetadata("kt47148.kt")
+            public void testKt47148() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/subtyping/kt47148.kt");
+            }
+
             @TestMetadata("kt-1457.kt")
             public void testKt_1457() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/subtyping/kt-1457.kt");