JVM IR: substitute generic type for inline class replacement function calls

The main change here is in `JvmInlineClassLowering.visitFunctionAccess`,
where we now store the substituted return type of the function as the
type of the call expression. Without it, the call could have a
meaningless type, e.g. some `T` which is inaccessible at that place, and
that could backfire in subsequent lowerings in codegen. For example, in
the `stringPlus.kt` test, it would prevent the code in
`FlattenStringConcatenationLowering.isStringPlusCall` from recognizing
and replacing the `String.plus` call, leading to a codegen exception.

Other changes are mostly cosmetics to make the code similar to
`visitFunctionReference`, and preventive optimizations for the case when
the substitution map is empty.

compiler/fir/fir2ir/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java

@@ -14117,6 +14117,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/inlineClasses/smartCastOnThisOfInlineClassType.kt");
         }
 
+        @TestMetadata("stringPlus.kt")
+        public void testStringPlus() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/stringPlus.kt");
+        }
+
         @TestMetadata("toStringCallingPrivateFun.kt")
         public void testToStringCallingPrivateFun() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/toStringCallingPrivateFun.kt");

compiler/ir/backend.common/src/org/jetbrains/kotlin/ir/util/IrTypeUtils.kt

@@ -80,7 +80,7 @@ fun IrType.substitute(params: List<IrTypeParameter>, arguments: List<IrType>): I
     substitute(params.map { it.symbol }.zip(arguments).toMap())
 
 fun IrType.substitute(substitutionMap: Map<IrTypeParameterSymbol, IrType>): IrType {
-    if (this !is IrSimpleType) return this
+    if (this !is IrSimpleType || substitutionMap.isEmpty()) return this
 
     val newAnnotations = annotations.map { it.deepCopyWithSymbols() }
 

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/JvmInlineClassLowering.kt

@@ -277,15 +277,16 @@ private class JvmInlineClassLowering(private val context: JvmBackendContext) : F
         if (expression.origin == InlineClassAbi.UNMANGLED_FUNCTION_REFERENCE)
             return super.visitFunctionReference(expression)
 
-        val function = context.inlineClassReplacements.getReplacementFunction(expression.symbol.owner)
+        val function = expression.symbol.owner
+        val replacement = context.inlineClassReplacements.getReplacementFunction(function)
             ?: return super.visitFunctionReference(expression)
 
         return IrFunctionReferenceImpl(
             expression.startOffset, expression.endOffset, expression.type,
-            function.symbol, function.typeParameters.size,
-            function.valueParameters.size, expression.reflectionTarget, expression.origin
+            replacement.symbol, replacement.typeParameters.size,
+            replacement.valueParameters.size, expression.reflectionTarget, expression.origin
         ).apply {
-            buildReplacement(expression.symbol.owner, expression, function)
+            buildReplacement(function, expression, replacement)
         }.copyAttributes(expression)
     }
 
@@ -293,10 +294,14 @@ private class JvmInlineClassLowering(private val context: JvmBackendContext) : F
         val function = expression.symbol.owner
         val replacement = context.inlineClassReplacements.getReplacementFunction(function)
             ?: return super.visitFunctionAccess(expression)
-        return context.createIrBuilder(currentScope!!.scope.scopeOwnerSymbol, expression.startOffset, expression.endOffset)
-            .irCall(replacement, expression.origin, expression.safeAs<IrCall>()?.superQualifierSymbol).apply {
-                buildReplacement(function, expression, replacement)
-            }
+
+        return IrCallImpl(
+            expression.startOffset, expression.endOffset, function.returnType.substitute(expression.typeSubstitutionMap),
+            replacement.symbol, replacement.typeParameters.size, replacement.valueParameters.size,
+            expression.origin, (expression as? IrCall)?.superQualifierSymbol
+        ).apply {
+            buildReplacement(function, expression, replacement)
+        }
     }
 
     private fun coerceInlineClasses(argument: IrExpression, from: IrType, to: IrType) =

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/util/IrUtils.kt

@@ -16,7 +16,10 @@ import org.jetbrains.kotlin.ir.expressions.impl.IrCallImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrConstructorCallImpl
 import org.jetbrains.kotlin.ir.expressions.impl.IrTypeOperatorCallImpl
 import org.jetbrains.kotlin.ir.symbols.*
-import org.jetbrains.kotlin.ir.types.*
+import org.jetbrains.kotlin.ir.types.IrSimpleType
+import org.jetbrains.kotlin.ir.types.IrType
+import org.jetbrains.kotlin.ir.types.isAny
+import org.jetbrains.kotlin.ir.types.isSubtypeOf
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.SpecialNames
 import org.jetbrains.kotlin.utils.DFS
@@ -512,10 +515,12 @@ val IrFunction.allTypeParameters: List<IrTypeParameter>
     else
         typeParameters
 
-fun IrMemberAccessExpression<*>.getTypeSubstitutionMap(irFunction: IrFunction): Map<IrTypeParameterSymbol, IrType> =
-    irFunction.allTypeParameters.withIndex().associate {
+fun IrMemberAccessExpression<*>.getTypeSubstitutionMap(irFunction: IrFunction): Map<IrTypeParameterSymbol, IrType> {
+    val typeParameters = irFunction.allTypeParameters
+    return if (typeParameters.isEmpty()) emptyMap() else typeParameters.withIndex().associate {
         it.value.symbol to getTypeArgument(it.index)!!
     }
+}
 
 val IrFunctionReference.typeSubstitutionMap: Map<IrTypeParameterSymbol, IrType>
     get() = getTypeSubstitutionMap(symbol.owner)
@@ -536,4 +541,4 @@ val IrFunction.originalFunction: IrFunction
     get() = (this as? IrAttributeContainer)?.attributeOwnerId as? IrFunction ?: this
 
 val IrProperty.originalProperty: IrProperty
-    get() = attributeOwnerId as? IrProperty ?: this
+    get() = attributeOwnerId as? IrProperty ?: this

compiler/testData/codegen/box/inlineClasses/stringPlus.kt

@@ -0,0 +1,9 @@
+// !LANGUAGE: +InlineClasses
+
+fun <T> foo(a: IC): T = a.value as T
+
+inline class IC(val value: String)
+
+fun box(): String {
+    return foo<String>(IC("O")) + "K"
+}

compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/funInterface/string.kt

@@ -1,6 +1,4 @@
 // !LANGUAGE: +InlineClasses
-// IGNORE_BACKEND: JVM_IR
-// IGNORE_BACKEND_FIR: JVM_IR
 
 fun <T> underlying(a: IC): T = bar(a) {
     it.value as T
@@ -48,4 +46,4 @@ fun box(): String {
     if (res != "OK") return "FAIL 3: $res"
 
     return "OK"
-}
+}

compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/lambda/string.kt

@@ -1,6 +1,4 @@
 // !LANGUAGE: +InlineClasses
-// IGNORE_BACKEND: JVM_IR
-// IGNORE_BACKEND_FIR: JVM_IR
 
 fun <T> underlying(a: IC): T = bar(a) {
     it.value as T
@@ -44,4 +42,4 @@ fun box(): String {
     if (res != "OK") return "FAIL 3: $res"
 
     return "OK"
-}
+}

compiler/testData/codegen/box/inlineClasses/unboxGenericParameter/objectLiteral/string.kt

@@ -1,6 +1,4 @@
 // !LANGUAGE: +InlineClasses
-// IGNORE_BACKEND: JVM_IR
-// IGNORE_BACKEND_FIR: JVM_IR
 
 fun <T> underlying(a: IC): T = bar(a, object : IFace<IC, T> {
     override fun call(ic: IC): T = ic.value as T
@@ -48,4 +46,4 @@ fun box(): String {
     if (res != "OK") return "FAIL 3: $res"
 
     return "OK"
-}
+}

compiler/testData/codegen/boxInline/inlineClasses/unboxGenericParameter/funInterface/string.kt

@@ -1,8 +1,4 @@
 // !LANGUAGE: +InlineClasses
-// IGNORE_BACKEND: JVM_IR
-// IGNORE_BACKEND_FIR: JVM_IR
-// IGNORE_BACKEND_MULTI_MODULE: JVM_IR, JVM_MULTI_MODULE_IR_AGAINST_OLD
-
 // FILE: inline.kt
 
 inline class IC(val value: String) {
@@ -47,4 +43,4 @@ fun box(): String {
     if (res != "OK") return "FAIL 3: $res"
 
     return "OK"
-}
+}

compiler/testData/codegen/boxInline/inlineClasses/unboxGenericParameter/lambda/string.kt

@@ -1,8 +1,4 @@
 // !LANGUAGE: +InlineClasses
-// IGNORE_BACKEND: JVM_IR
-// IGNORE_BACKEND_FIR: JVM_IR
-// IGNORE_BACKEND_MULTI_MODULE: JVM_IR, JVM_MULTI_MODULE_IR_AGAINST_OLD
-
 // FILE: inline.kt
 
 inline class IC(val value: String) {
@@ -43,4 +39,4 @@ fun box(): String {
     if (res != "OK") return "FAIL 3: $res"
 
     return "OK"
-}
+}

compiler/testData/codegen/boxInline/inlineClasses/unboxGenericParameter/objectLiteral/string.kt

@@ -1,8 +1,4 @@
 // !LANGUAGE: +InlineClasses
-// IGNORE_BACKEND: JVM_IR
-// IGNORE_BACKEND_FIR: JVM_IR
-// IGNORE_BACKEND_MULTI_MODULE: JVM_IR, JVM_MULTI_MODULE_IR_AGAINST_OLD
-
 // FILE: inline.kt
 
 inline class IC(val value: String) {
@@ -47,4 +43,4 @@ fun box(): String {
     if (res != "OK") return "FAIL 3: $res"
 
     return "OK"
-}
+}

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -15517,6 +15517,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/inlineClasses/smartCastOnThisOfInlineClassType.kt");
         }
 
+        @TestMetadata("stringPlus.kt")
+        public void testStringPlus() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/stringPlus.kt");
+        }
+
         @TestMetadata("toStringCallingPrivateFun.kt")
         public void testToStringCallingPrivateFun() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/toStringCallingPrivateFun.kt");

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -15522,6 +15522,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/inlineClasses/smartCastOnThisOfInlineClassType.kt");
         }
 
+        @TestMetadata("stringPlus.kt")
+        public void testStringPlus() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/stringPlus.kt");
+        }
+
         @TestMetadata("toStringCallingPrivateFun.kt")
         public void testToStringCallingPrivateFun() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/toStringCallingPrivateFun.kt");

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -14117,6 +14117,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/inlineClasses/smartCastOnThisOfInlineClassType.kt");
         }
 
+        @TestMetadata("stringPlus.kt")
+        public void testStringPlus() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/stringPlus.kt");
+        }
+
         @TestMetadata("toStringCallingPrivateFun.kt")
         public void testToStringCallingPrivateFun() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/toStringCallingPrivateFun.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java

@@ -12122,6 +12122,11 @@ public class IrJsCodegenBoxES6TestGenerated extends AbstractIrJsCodegenBoxES6Tes
             runTest("compiler/testData/codegen/box/inlineClasses/smartCastOnThisOfInlineClassType.kt");
         }
 
+        @TestMetadata("stringPlus.kt")
+        public void testStringPlus() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/stringPlus.kt");
+        }
+
         @TestMetadata("toStringCallingPrivateFun.kt")
         public void testToStringCallingPrivateFun() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/toStringCallingPrivateFun.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java

@@ -12122,6 +12122,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/inlineClasses/smartCastOnThisOfInlineClassType.kt");
         }
 
+        @TestMetadata("stringPlus.kt")
+        public void testStringPlus() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/stringPlus.kt");
+        }
+
         @TestMetadata("toStringCallingPrivateFun.kt")
         public void testToStringCallingPrivateFun() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/toStringCallingPrivateFun.kt");

js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java

@@ -12187,6 +12187,11 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/inlineClasses/smartCastOnThisOfInlineClassType.kt");
         }
 
+        @TestMetadata("stringPlus.kt")
+        public void testStringPlus() throws Exception {
+            runTest("compiler/testData/codegen/box/inlineClasses/stringPlus.kt");
+        }
+
         @TestMetadata("toStringCallingPrivateFun.kt")
         public void testToStringCallingPrivateFun() throws Exception {
             runTest("compiler/testData/codegen/box/inlineClasses/toStringCallingPrivateFun.kt");