PSI2IR/FIR2IR: do not approximate T!! before translation

This leads to weird effects when it's in a contravariant position,
because it's approximated by Nothing.

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrTypeConverter.kt

@@ -67,6 +67,14 @@ class Fir2IrTypeConverter(
 
     private val typeApproximator = ConeTypeApproximator(session.typeContext, session.languageVersionSettings)
 
+    private val typeApproximatorConfiguration =
+        object : TypeApproximatorConfiguration.AllFlexibleSameValue() {
+            override val allFlexible: Boolean get() = true
+            override val errorType: Boolean get() = true
+            override val integerLiteralType: Boolean get() = true
+            override val intersectionTypesInContravariantPositions: Boolean get() = true
+        }
+
     fun FirTypeRef.toIrType(typeContext: ConversionTypeContext = ConversionTypeContext.DEFAULT): IrType {
         capturedTypeCache.clear()
         return when (this) {
@@ -232,11 +240,9 @@ class Fir2IrTypeConverter(
                 } else null
             }
         }
-        val typeWithSpecifiedIntersectionTypes = substitutor.substituteOrSelf(type)
+        return substitutor.substituteOrSelf(type).let {
-        return typeApproximator.approximateToSuperType(
+            typeApproximator.approximateToSuperType(it, typeApproximatorConfiguration) ?: it
-            typeWithSpecifiedIntersectionTypes,
+        }
-            TypeApproximatorConfiguration.PublicDeclaration
-        ) ?: type
     }
 }
 

compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/TypeTranslatorImpl.kt

@@ -8,9 +8,7 @@ package org.jetbrains.kotlin.psi2ir.generators
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.descriptors.ModuleDescriptor
 import org.jetbrains.kotlin.ir.util.*
-import org.jetbrains.kotlin.types.CommonSupertypes
+import org.jetbrains.kotlin.types.*
-import org.jetbrains.kotlin.types.KotlinType
-import org.jetbrains.kotlin.types.TypeApproximator
 
 class TypeTranslatorImpl(
     symbolTable: ReferenceSymbolTable,
@@ -25,8 +23,18 @@ class TypeTranslatorImpl(
 
     private val typeApproximatorForNI = TypeApproximator(moduleDescriptor.builtIns, languageVersionSettings)
 
+    private val typeApproximatorConfiguration =
+        object : TypeApproximatorConfiguration.AllFlexibleSameValue() {
+            override val allFlexible: Boolean get() = true
+            override val errorType: Boolean get() = true
+            override val integerLiteralType: Boolean get() = true
+            override val intersectionTypesInContravariantPositions: Boolean get() = true
+        }
+
     override fun approximateType(type: KotlinType): KotlinType =
-        typeApproximatorForNI.approximateDeclarationType(type, local = false)
+        substituteAlternativesInPublicType(type).let {
+            typeApproximatorForNI.approximateToSuperType(it, typeApproximatorConfiguration) ?: it
+        }
 
     override fun commonSupertype(types: Collection<KotlinType>): KotlinType =
         CommonSupertypes.commonSupertype(types)

compiler/testData/codegen/box/callableReference/function/argumentTypes.kt

@@ -1,11 +1,7 @@
-// IGNORE_BACKEND: JVM_IR
-// IGNORE_BACKEND_FIR: JVM_IR
-// DONT_TARGET_EXACT_BACKEND: WASM
-// WASM_MUTE_REASON: CALLABLE_REFERENCES_FAIL
 fun <T> id(x: T): T = x
 fun <T> String.extId(x: T): T = x
 
-fun <T> foo(value: T?): T? = value?.let(::id) // KFunction1<Nothing, T>
+fun <T> foo(value: T?): T? = value?.let(::id) // ::id = KFunction1<T!!, T!!>
 fun <T> bar(value: T?): T? = value?.let(""::extId)
 
-fun box() = foo("O")!! + foo("K")!!
+fun box() = foo("O")!! + bar("K")!!

compiler/testData/codegen/box/callableReference/function/argumentTypesNoinline.kt

@@ -1,13 +1,11 @@
-// IGNORE_BACKEND: JVM_IR
-// IGNORE_BACKEND_FIR: JVM_IR
 // DONT_TARGET_EXACT_BACKEND: WASM
-// WASM_MUTE_REASON: CALLABLE_REFERENCES_FAIL
+// WASM_MUTE_REASON: BINDING_RECEIVERS
 fun <T> id(x: T): T = x
 fun <T> String.extId(x: T): T = x
 
 fun <T, R> T.myLet(block: (T) -> R): R = block(this)
 
-fun <T> foo(value: T?): T? = value?.myLet(::id) // KFunction1<Nothing, T>
+fun <T> foo(value: T?): T? = value?.myLet(::id) // ::id = KFunction1<T!!, T!!>
 fun <T> bar(value: T?): T? = value?.myLet(""::extId)
 
-fun box() = foo("O")!! + foo("K")!!
+fun box() = foo("O")!! + bar("K")!!

compiler/testData/ir/irText/types/intersectionType1_NI.kt.txt

@@ -12,7 +12,7 @@ fun <S : Any?> select(x: S, y: S): S {
 }
 
 fun <T : Any?> foo(a: Array<In<T>>, b: Array<In<String>>): Boolean {
-  return select<Array<out In<Nothing>>>(x = a, y = b).get(index = 0).ofType<Any?>(y = true)
+  return select<Array<out In<Nothing>>>(x = a, y = b).get(index = 0).ofType<Any>(y = true)
 }
 
 inline fun <reified K : Any?> In<K>.ofType(y: Any?): Boolean {

compiler/testData/ir/irText/types/intersectionType1_NI.txt

@@ -33,7 +33,7 @@ FILE fqName:<root> fileName:/intersectionType1_NI.kt
     BLOCK_BODY
       RETURN type=kotlin.Nothing from='public final fun foo <T> (a: kotlin.Array<<root>.In<T of <root>.foo>>, b: kotlin.Array<<root>.In<kotlin.String>>): kotlin.Boolean declared in <root>'
         CALL 'public final fun ofType <K> (y: kotlin.Any?): kotlin.Boolean [inline] declared in <root>' type=kotlin.Boolean origin=null
-          <K>: kotlin.Any?
+          <K>: kotlin.Any
           $receiver: CALL 'public final fun get (index: kotlin.Int): T of kotlin.Array [operator] declared in kotlin.Array' type=<root>.In<kotlin.Nothing> origin=GET_ARRAY_ELEMENT
             $this: CALL 'public final fun select <S> (x: S of <root>.select, y: S of <root>.select): S of <root>.select declared in <root>' type=kotlin.Array<out <root>.In<kotlin.Nothing>> origin=null
               <S>: kotlin.Array<out <root>.In<kotlin.Nothing>>

js/js.tests/tests-gen/org/jetbrains/kotlin/js/test/wasm/semantics/IrCodegenBoxWasmTestGenerated.java

@@ -1437,6 +1437,11 @@ public class IrCodegenBoxWasmTestGenerated extends AbstractIrCodegenBoxWasmTest
                 KtTestUtil.assertAllTestsPresentByMetadataWithExcluded(this.getClass(), new File("compiler/testData/codegen/box/callableReference/function"), Pattern.compile("^([^_](.+))\\.kt$"), null, TargetBackend.WASM, true);
             }
 
+            @TestMetadata("argumentTypes.kt")
+            public void testArgumentTypes() throws Exception {
+                runTest("compiler/testData/codegen/box/callableReference/function/argumentTypes.kt");
+            }
+
             @TestMetadata("booleanNotIntrinsic.kt")
             public void testBooleanNotIntrinsic() throws Exception {
                 runTest("compiler/testData/codegen/box/callableReference/function/booleanNotIntrinsic.kt");