K2: report empty intersection warnings from completion properly

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirLightTreeBlackBoxCodegenTestGenerated.java

@@ -18325,6 +18325,12 @@ public class FirLightTreeBlackBoxCodegenTestGenerated extends AbstractFirLightTr
             runTest("compiler/testData/codegen/box/fir/differentSinceKotlin.kt");
         }
 
+        @Test
+        @TestMetadata("emptyIntersectionWarning.kt")
+        public void testEmptyIntersectionWarning() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/emptyIntersectionWarning.kt");
+        }
+
         @Test
         @TestMetadata("ExtensionAlias.kt")
         public void testExtensionAlias() throws Exception {

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirPsiBlackBoxCodegenTestGenerated.java

@@ -18325,6 +18325,12 @@ public class FirPsiBlackBoxCodegenTestGenerated extends AbstractFirPsiBlackBoxCo
             runTest("compiler/testData/codegen/box/fir/differentSinceKotlin.kt");
         }
 
+        @Test
+        @TestMetadata("emptyIntersectionWarning.kt")
+        public void testEmptyIntersectionWarning() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/emptyIntersectionWarning.kt");
+        }
+
         @Test
         @TestMetadata("ExtensionAlias.kt")
         public void testExtensionAlias() throws Exception {

compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/transformers/FirCallCompletionResultsWriterTransformer.kt

@@ -802,8 +802,9 @@ class FirCallCompletionResultsWriterTransformer(
         return varargArgumentsExpression
     }
 
+    // TODO: report warning with a checker and return true here only in case of errors
     private fun FirNamedReferenceWithCandidate.hasAdditionalResolutionErrors(): Boolean =
-        candidate.system.errors.any { it is InferredEmptyIntersection && it.kind.isDefinitelyEmpty }
+        candidate.system.errors.any { it is InferredEmptyIntersection }
 
     private fun FirNamedReferenceWithCandidate.toResolvedReference(): FirNamedReference {
         val errorDiagnostic = when {

compiler/testData/codegen/box/fir/emptyIntersectionWarning.kt

@@ -0,0 +1,13 @@
+// TARGET_BACKEND: JVM_IR
+// IGNORE_BACKEND_K1: JVM_IR
+
+interface I
+class View1
+
+fun <T : View1> findViewById1(): T? = null
+fun test1(): I? = findViewById1()
+
+fun box(): String {
+    test1()
+    return "OK"
+}

compiler/testData/diagnostics/tests/inference/coercionToUnit/afterBareReturn.fir.kt

@@ -1,41 +0,0 @@
-interface I
-open class C
-
-fun completed(): String = "..."
-
-fun <T> incomplete(): T = null!!
-
-fun <T : I> incompatibleI(): T = null!!
-fun <T : C> incompatibleC(): T = null!!
-
-val p = false
-
-fun expectUnit(x: Unit) = x
-
-fun test1() = run {
-    if (p) return@run
-    completed() // ok, not returned
-}
-
-fun test2() = run {
-    if (p) return@run
-    incomplete() // ? either uninferred T or Unit
-}
-
-fun test3() = run {
-    if (p) return@run
-    incompatibleI() // ? either uninferred T or error (Unit </: I)
-}
-
-fun test4() = <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>run<!> {
-    if (p) return@run
-    incompatibleC() // ? either uninferred T or error (Unit </: C)
-}
-
-fun main() {
-    // all ok
-    expectUnit(test1())
-    expectUnit(test2())
-    expectUnit(test3())
-    expectUnit(test4())
-}

compiler/testData/diagnostics/tests/inference/coercionToUnit/afterBareReturn.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 interface I
 open class C
 

compiler/testData/diagnostics/tests/resolve/specialConstructions/exclExclAsCall.fir.kt

@@ -13,7 +13,7 @@ fun <T: A> emptyNullableListOfA(): List<T>? = null
 
 fun testExclExcl() {
     <!INFERRED_TYPE_VARIABLE_INTO_POSSIBLE_EMPTY_INTERSECTION("T; a/A, kotlin/Int; final class and interface")!>doList<!>(emptyNullableListOfA()!!) //should be an error here
-    val l: List<Int> = <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.collections.List<a.A & kotlin.Int>")!>id(emptyNullableListOfA()!!)<!>
+    val l: List<Int> = <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.collections.List<a.A & kotlin.Int>")!><!INFERRED_TYPE_VARIABLE_INTO_POSSIBLE_EMPTY_INTERSECTION!>id<!>(emptyNullableListOfA()!!)<!>
 
     doList(strangeNullableList { doInt(it) }!!) //lambda should be analyzed (at completion phase)
 }

compiler/testData/diagnostics/tests/typeParameters/dontIntersectUpperBoundWithExpectedType.fir.kt

@@ -14,4 +14,4 @@ fun main() {
 
 
 fun <T : Appendable> wtf(): T = TODO()
-val bar: Int = wtf() // happily compiles
+val bar: Int = <!INFERRED_TYPE_VARIABLE_INTO_POSSIBLE_EMPTY_INTERSECTION!>wtf<!>() // happily compiles

compiler/testData/diagnostics/tests/typeParameters/kt42472.fir.kt

@@ -7,6 +7,6 @@ fun interface ReadOnlyProperty<in T, out V> {
 }
 
 class Problem {
-    val variable: Int by delegate() // delegate returns `ReadOnlyProperty<Problem, {CharSequence & Int}>`
+    val variable: Int by <!DELEGATE_SPECIAL_FUNCTION_NONE_APPLICABLE, INFERRED_TYPE_VARIABLE_INTO_POSSIBLE_EMPTY_INTERSECTION!>delegate()<!> // delegate returns `ReadOnlyProperty<Problem, {CharSequence & Int}>`
     fun <T : CharSequence> delegate() = null <!CAST_NEVER_SUCCEEDS!>as<!> ReadOnlyProperty<Problem, T>
 }

compiler/testData/diagnostics/tests/typeParameters/kt46186withEmptyIntersections.fir.kt

@@ -1,84 +0,0 @@
-// !DIAGNOSTICS: -FINAL_UPPER_BOUND -CAST_NEVER_SUCCEEDS
-// !LANGUAGE: +AllowEmptyIntersectionsInResultTypeResolver
-
-interface I
-
-class View1
-open class View2
-interface View3
-abstract class View4
-interface View5
-
-fun <T: View1> findViewById1(): T = null as T
-fun test1(): I = findViewById1()
-
-fun <T: View2> findViewById2(): T = null as T
-fun test2(): I = findViewById2()
-
-inline fun <reified T: View1> findViewById3(): T = null as T
-fun test3(): I = findViewById3()
-
-inline fun <reified T: View2> findViewById4(): T = null as T
-fun test4(): I = findViewById4()
-
-fun <T: View3> findViewById5(): T = null as T
-fun test5(): I = findViewById5()
-
-inline fun <reified T: View3> findViewById6(): T = null as T
-fun test6(): I = findViewById6()
-
-fun <T: View4> findViewById7(): T = null as T
-fun test7(): I = findViewById7()
-
-inline fun <reified T: View4> findViewById8(): T = null as T
-fun test8(): I = findViewById8()
-
-fun <T> findViewById9(): T where T: View3, T: View5 = null as T
-fun test9(): I = findViewById9()
-
-inline fun <reified T> findViewById10(): T where T: View3, T: View5 = null as T
-fun test10(): I = findViewById10()
-
-fun <T: View2> findViewById11(): T = null as T
-fun test11(): View4 = <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>findViewById11<!>()
-
-object Obj {
-    fun <T: I> findViewById1(): T = null as T
-    fun test1(): View1 = findViewById1()
-
-    fun <T: I> findViewById2(): T = null as T
-    fun test2(): View2 = findViewById2()
-
-    inline fun <reified T: I> findViewById3(): T = null as T
-    fun test3(): View1 = findViewById3()
-
-    inline fun <reified T: I> findViewById4(): T = null as T
-    fun test4(): View2 = findViewById4()
-
-    fun <T: I> findViewById5(): T = null as T
-    fun test5(): View3 = findViewById5()
-
-    inline fun <reified T: I> findViewById6(): T = null as T
-    fun test6(): View3 = findViewById6()
-
-    fun <T: I> findViewById7(): T = null as T
-    fun test7(): View4 = findViewById7()
-
-    inline fun <reified T: I> findViewById8(): T = null as T
-    fun test8(): View4 = findViewById8()
-
-    fun <T> findViewById9(): T where T: View3, T: View5 = null as T
-    fun test9(): View1 = findViewById9()
-
-    inline fun <reified T> findViewById10(): T where T: View3, T: View5 = null as T
-    fun test10(): View1 = findViewById10()
-
-    fun <T: View2> findViewById11(): T = null as T
-    fun test11(): View4 = <!INFERRED_TYPE_VARIABLE_INTO_EMPTY_INTERSECTION_WARNING!>findViewById11<!>()
-}
-
-interface A
-open class B {
-    fun <T> f(): T where T : A, T : B = null as T
-    fun g(): A = f()
-}

compiler/testData/diagnostics/tests/typeParameters/kt46186withEmptyIntersections.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -FINAL_UPPER_BOUND -CAST_NEVER_SUCCEEDS
 // !LANGUAGE: +AllowEmptyIntersectionsInResultTypeResolver
 

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

@@ -18325,6 +18325,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/fir/differentSinceKotlin.kt");
         }
 
+        @Test
+        @TestMetadata("emptyIntersectionWarning.kt")
+        public void testEmptyIntersectionWarning() throws Exception {
+            runTest("compiler/testData/codegen/box/fir/emptyIntersectionWarning.kt");
+        }
+
         @Test
         @TestMetadata("ExtensionAlias.kt")
         public void testExtensionAlias() throws Exception {