PSI2IR / FIR2IR: do not create temporaries for adapted references

Arguments to function references behave the same as arguments to
function calls and should be evaluated once regardless, so the temporary
is unnecessary.

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/generators/AdapterGenerator.kt

@@ -154,22 +154,15 @@ internal class AdapterGenerator(
             if (boundReceiver == null) {
                 IrFunctionExpressionImpl(startOffset, endOffset, type, irAdapterFunction, IrStatementOrigin.ADAPTED_FUNCTION_REFERENCE)
             } else {
+                // TODO add a bound receiver property to IrFunctionExpressionImpl?
                 val irAdapterRef = IrFunctionReferenceImpl(
                     startOffset, endOffset, type, irAdapterFunction.symbol, irAdapterFunction.typeParameters.size,
                     irAdapterFunction.valueParameters.size, null, IrStatementOrigin.ADAPTED_FUNCTION_REFERENCE
                 )
-                val statements = SmartList<IrStatement>()
+                IrBlockImpl(startOffset, endOffset, type, IrStatementOrigin.ADAPTED_FUNCTION_REFERENCE).apply {
-                if (boundReceiver.isSafeToUseWithoutCopying()) {
+                    statements.add(irAdapterFunction)
-                    irAdapterRef.extensionReceiver = boundReceiver
+                    statements.add(irAdapterRef.apply { extensionReceiver = boundReceiver })
-                } else {
-                    val (irVariable, irVariableSymbol) = createTemporaryVariable(boundReceiver.deepCopyWithSymbols(), conversionScope)
-                    irAdapterRef.extensionReceiver = IrGetValueImpl(startOffset, endOffset, irVariableSymbol)
-                    statements.add(irVariable)
                 }
-                statements.add(irAdapterFunction)
-                statements.add(irAdapterRef)
-
-                IrBlockImpl(startOffset, endOffset, type, IrStatementOrigin.ADAPTED_FUNCTION_REFERENCE, statements)
             }
         }
     }

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

@@ -153,35 +153,26 @@ class ReflectionReferencesGenerator(statementGenerator: StatementGenerator) : St
             resolvedCall.dispatchReceiver, resolvedCall.extensionReceiver,
             isSafe = false
         ).call { dispatchReceiverValue, extensionReceiverValue ->
-            val irAdapterRef = IrFunctionReferenceImpl(
-                startOffset, endOffset, irFunctionalType, irAdapterFun.symbol, irAdapterFun.typeParameters.size,
-                irAdapterFun.valueParameters.size, null, IrStatementOrigin.ADAPTED_FUNCTION_REFERENCE
-            )
-
             val irDispatchReceiver = dispatchReceiverValue?.loadIfExists()
             val irExtensionReceiver = extensionReceiverValue?.loadIfExists()
             check(irDispatchReceiver == null || irExtensionReceiver == null) {
                 "Bound callable reference cannot have both receivers: $adapteeDescriptor"
             }
             val receiver = irDispatchReceiver ?: irExtensionReceiver
-
             if (receiver == null) {
                 IrFunctionExpressionImpl(
                     startOffset, endOffset, irFunctionalType, irAdapterFun, IrStatementOrigin.ADAPTED_FUNCTION_REFERENCE
                 )
             } else {
-                val statements = SmartList<IrStatement>()
+                // TODO add a bound receiver property to IrFunctionExpressionImpl?
-                if (receiver.isSafeToUseWithoutCopying()) {
+                val irAdapterRef = IrFunctionReferenceImpl(
-                    irAdapterRef.extensionReceiver = receiver
+                    startOffset, endOffset, irFunctionalType, irAdapterFun.symbol, irAdapterFun.typeParameters.size,
-                } else {
+                    irAdapterFun.valueParameters.size, null, IrStatementOrigin.ADAPTED_FUNCTION_REFERENCE
-                    val irVariable = statementGenerator.scope.createTemporaryVariable(receiver, "receiver")
+                )
-                    irAdapterRef.extensionReceiver = IrGetValueImpl(startOffset, endOffset, irVariable.symbol)
+                IrBlockImpl(startOffset, endOffset, irFunctionalType, IrStatementOrigin.ADAPTED_FUNCTION_REFERENCE).apply {
-                    statements.add(irVariable)
+                    statements.add(irAdapterFun)
+                    statements.add(irAdapterRef.apply { extensionReceiver = receiver })
                 }
-                statements.add(irAdapterFun)
-                statements.add(irAdapterRef)
-
-                IrBlockImpl(startOffset, endOffset, irFunctionalType, IrStatementOrigin.ADAPTED_FUNCTION_REFERENCE, statements)
             }
         }
     }

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

@@ -529,12 +529,6 @@ val IrDeclaration.isFileClass: Boolean
 val IrValueDeclaration.isImmutable: Boolean
     get() = this is IrValueParameter || this is IrVariable && !isVar
 
-fun IrExpression.isSafeToUseWithoutCopying() =
-    this is IrGetObjectValue ||
-            this is IrGetEnumValue ||
-            this is IrConst<*> ||
-            this is IrGetValue && symbol.isBound && symbol.owner.isImmutable
-
 val IrStatementOrigin?.isLambda: Boolean
     get() = this == IrStatementOrigin.LAMBDA || this == IrStatementOrigin.ANONYMOUS_FUNCTION
 

compiler/testData/ir/irText/expressions/callableReferences/constructorWithAdaptedArguments.txt

@@ -100,8 +100,6 @@ FILE fqName:<root> fileName:/constructorWithAdaptedArguments.kt
       RETURN type=kotlin.Nothing from='public final fun testInnerClassConstructorCapturingOuter (): kotlin.Any declared in <root>'
         CALL 'public final fun use (fn: kotlin.Function1<kotlin.Int, kotlin.Any>): kotlin.Any declared in <root>' type=kotlin.Any origin=null
           fn: BLOCK type=kotlin.Function1<kotlin.Int, <root>.Outer.Inner> origin=ADAPTED_FUNCTION_REFERENCE
-            VAR IR_TEMPORARY_VARIABLE name:tmp_0 type:<root>.Outer [val]
-              CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.Outer' type=<root>.Outer origin=null
             FUN ADAPTER_FOR_CALLABLE_REFERENCE name:<init> visibility:local modality:FINAL <> ($receiver:<root>.Outer, p0:kotlin.Int) returnType:<root>.Outer.Inner
               $receiver: VALUE_PARAMETER ADAPTER_PARAMETER_FOR_CALLABLE_REFERENCE name:receiver type:<root>.Outer
               VALUE_PARAMETER ADAPTER_PARAMETER_FOR_CALLABLE_REFERENCE name:p0 index:0 type:kotlin.Int
@@ -112,4 +110,4 @@ FILE fqName:<root> fileName:/constructorWithAdaptedArguments.kt
                     xs: VARARG type=kotlin.IntArray varargElementType=kotlin.Int
                       GET_VAR 'p0: kotlin.Int declared in <root>.testInnerClassConstructorCapturingOuter.<init>' type=kotlin.Int origin=null
             FUNCTION_REFERENCE 'local final fun <init> (p0: kotlin.Int): <root>.Outer.Inner declared in <root>.testInnerClassConstructorCapturingOuter' type=kotlin.Function1<kotlin.Int, <root>.Outer.Inner> origin=ADAPTED_FUNCTION_REFERENCE reflectionTarget=null
-              $receiver: GET_VAR 'val tmp_0: <root>.Outer [val] declared in <root>.testInnerClassConstructorCapturingOuter' type=<root>.Outer origin=null
+              $receiver: CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.Outer' type=<root>.Outer origin=null

compiler/testData/ir/irText/expressions/callableReferences/suspendConversion.fir.txt

@@ -108,8 +108,6 @@ FILE fqName:<root> fileName:/suspendConversion.kt
     BLOCK_BODY
       CALL 'public final fun useSuspend (fn: kotlin.coroutines.SuspendFunction0<kotlin.Unit>): kotlin.Unit declared in <root>' type=kotlin.Unit origin=null
         fn: BLOCK type=kotlin.coroutines.SuspendFunction0<kotlin.Unit> origin=ADAPTED_FUNCTION_REFERENCE
-          VAR IR_TEMPORARY_VARIABLE name:tmp_0 type:<root>.C [val]
-            CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.C' type=<root>.C origin=null
           FUN ADAPTER_FOR_CALLABLE_REFERENCE name:bar visibility:local modality:FINAL <> ($receiver:<root>.C) returnType:kotlin.Unit [suspend]
             $receiver: VALUE_PARAMETER ADAPTER_PARAMETER_FOR_CALLABLE_REFERENCE name:receiver type:<root>.C
             BLOCK_BODY

compiler/testData/ir/irText/expressions/callableReferences/suspendConversion.txt

@@ -109,12 +109,10 @@ FILE fqName:<root> fileName:/suspendConversion.kt
     BLOCK_BODY
       CALL 'public final fun useSuspend (fn: kotlin.coroutines.SuspendFunction0<kotlin.Unit>): kotlin.Unit declared in <root>' type=kotlin.Unit origin=null
         fn: BLOCK type=kotlin.coroutines.SuspendFunction0<kotlin.Unit> origin=ADAPTED_FUNCTION_REFERENCE
-          VAR IR_TEMPORARY_VARIABLE name:tmp_0 type:<root>.C [val]
-            CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.C' type=<root>.C origin=null
           FUN ADAPTER_FOR_CALLABLE_REFERENCE name:bar visibility:local modality:FINAL <> ($receiver:<root>.C) returnType:kotlin.Unit [suspend]
             $receiver: VALUE_PARAMETER ADAPTER_PARAMETER_FOR_CALLABLE_REFERENCE name:receiver type:<root>.C
             BLOCK_BODY
               CALL 'public final fun bar (): kotlin.Unit declared in <root>.C' type=kotlin.Unit origin=null
                 $this: GET_VAR 'receiver: <root>.C declared in <root>.testWithBoundReceiver.bar' type=<root>.C origin=ADAPTED_FUNCTION_REFERENCE
           FUNCTION_REFERENCE 'local final fun bar (): kotlin.Unit [suspend] declared in <root>.testWithBoundReceiver' type=kotlin.coroutines.SuspendFunction0<kotlin.Unit> origin=ADAPTED_FUNCTION_REFERENCE reflectionTarget=null
-            $receiver: GET_VAR 'val tmp_0: <root>.C [val] declared in <root>.testWithBoundReceiver' type=<root>.C origin=null
+            $receiver: CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.C' type=<root>.C origin=null

compiler/testData/ir/irText/expressions/callableReferences/withArgumentAdaptationAndReceiver.fir.txt

@@ -55,8 +55,6 @@ FILE fqName:<root> fileName:/withArgumentAdaptationAndReceiver.kt
           CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.Host' type=<root>.Host origin=null
         CALL 'public final fun use (fn: kotlin.Function1<kotlin.Int, kotlin.Unit>): kotlin.Unit declared in <root>' type=kotlin.Unit origin=null
           fn: BLOCK type=kotlin.Function1<kotlin.Int, kotlin.Unit> origin=ADAPTED_FUNCTION_REFERENCE
-            VAR IR_TEMPORARY_VARIABLE name:tmp_0 type:<root>.Host [val]
-              GET_VAR 'var h: <root>.Host [var] declared in <root>.Host.testBoundReceiverLocalVar' type=<root>.Host origin=null
             FUN ADAPTER_FOR_CALLABLE_REFERENCE name:withVararg visibility:local modality:FINAL <> ($receiver:<root>.Host, p0:kotlin.Int) returnType:kotlin.Unit
               $receiver: VALUE_PARAMETER ADAPTER_PARAMETER_FOR_CALLABLE_REFERENCE name:receiver type:<root>.Host
               VALUE_PARAMETER ADAPTER_PARAMETER_FOR_CALLABLE_REFERENCE name:p0 index:0 type:kotlin.Int
@@ -88,8 +86,6 @@ FILE fqName:<root> fileName:/withArgumentAdaptationAndReceiver.kt
       BLOCK_BODY
         CALL 'public final fun use (fn: kotlin.Function1<kotlin.Int, kotlin.Unit>): kotlin.Unit declared in <root>' type=kotlin.Unit origin=null
           fn: BLOCK type=kotlin.Function1<kotlin.Int, kotlin.Unit> origin=ADAPTED_FUNCTION_REFERENCE
-            VAR IR_TEMPORARY_VARIABLE name:tmp_1 type:<root>.Host [val]
-              CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.Host' type=<root>.Host origin=null
             FUN ADAPTER_FOR_CALLABLE_REFERENCE name:withVararg visibility:local modality:FINAL <> ($receiver:<root>.Host, p0:kotlin.Int) returnType:kotlin.Unit
               $receiver: VALUE_PARAMETER ADAPTER_PARAMETER_FOR_CALLABLE_REFERENCE name:receiver type:<root>.Host
               VALUE_PARAMETER ADAPTER_PARAMETER_FOR_CALLABLE_REFERENCE name:p0 index:0 type:kotlin.Int

compiler/testData/ir/irText/expressions/callableReferences/withArgumentAdaptationAndReceiver.txt

@@ -58,8 +58,6 @@ FILE fqName:<root> fileName:/withArgumentAdaptationAndReceiver.kt
           CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.Host' type=<root>.Host origin=null
         CALL 'public final fun use (fn: kotlin.Function1<kotlin.Int, kotlin.Unit>): kotlin.Unit declared in <root>' type=kotlin.Unit origin=null
           fn: BLOCK type=kotlin.Function1<kotlin.Int, kotlin.Unit> origin=ADAPTED_FUNCTION_REFERENCE
-            VAR IR_TEMPORARY_VARIABLE name:tmp_0 type:<root>.Host [val]
-              GET_VAR 'var h: <root>.Host [var] declared in <root>.Host.testBoundReceiverLocalVar' type=<root>.Host origin=null
             FUN ADAPTER_FOR_CALLABLE_REFERENCE name:withVararg visibility:local modality:FINAL <> ($receiver:<root>.Host, p0:kotlin.Int) returnType:kotlin.Unit
               $receiver: VALUE_PARAMETER ADAPTER_PARAMETER_FOR_CALLABLE_REFERENCE name:receiver type:<root>.Host
               VALUE_PARAMETER ADAPTER_PARAMETER_FOR_CALLABLE_REFERENCE name:p0 index:0 type:kotlin.Int
@@ -70,7 +68,7 @@ FILE fqName:<root> fileName:/withArgumentAdaptationAndReceiver.kt
                     xs: VARARG type=kotlin.IntArray varargElementType=kotlin.Int
                       GET_VAR 'p0: kotlin.Int declared in <root>.Host.testBoundReceiverLocalVar.withVararg' type=kotlin.Int origin=null
             FUNCTION_REFERENCE 'local final fun withVararg (p0: kotlin.Int): kotlin.Unit declared in <root>.Host.testBoundReceiverLocalVar' type=kotlin.Function1<kotlin.Int, kotlin.Unit> origin=ADAPTED_FUNCTION_REFERENCE reflectionTarget=null
-              $receiver: GET_VAR 'val tmp_0: <root>.Host [val] declared in <root>.Host.testBoundReceiverLocalVar' type=<root>.Host origin=null
+              $receiver: GET_VAR 'var h: <root>.Host [var] declared in <root>.Host.testBoundReceiverLocalVar' type=<root>.Host origin=null
     FUN name:testBoundReceiverParameter visibility:public modality:FINAL <> ($this:<root>.Host, h:<root>.Host) returnType:kotlin.Unit
       $this: VALUE_PARAMETER name:<this> type:<root>.Host
       VALUE_PARAMETER name:h index:0 type:<root>.Host
@@ -93,8 +91,6 @@ FILE fqName:<root> fileName:/withArgumentAdaptationAndReceiver.kt
       BLOCK_BODY
         CALL 'public final fun use (fn: kotlin.Function1<kotlin.Int, kotlin.Unit>): kotlin.Unit declared in <root>' type=kotlin.Unit origin=null
           fn: BLOCK type=kotlin.Function1<kotlin.Int, kotlin.Unit> origin=ADAPTED_FUNCTION_REFERENCE
-            VAR IR_TEMPORARY_VARIABLE name:tmp_1 type:<root>.Host [val]
-              CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.Host' type=<root>.Host origin=null
             FUN ADAPTER_FOR_CALLABLE_REFERENCE name:withVararg visibility:local modality:FINAL <> ($receiver:<root>.Host, p0:kotlin.Int) returnType:kotlin.Unit
               $receiver: VALUE_PARAMETER ADAPTER_PARAMETER_FOR_CALLABLE_REFERENCE name:receiver type:<root>.Host
               VALUE_PARAMETER ADAPTER_PARAMETER_FOR_CALLABLE_REFERENCE name:p0 index:0 type:kotlin.Int
@@ -105,7 +101,7 @@ FILE fqName:<root> fileName:/withArgumentAdaptationAndReceiver.kt
                     xs: VARARG type=kotlin.IntArray varargElementType=kotlin.Int
                       GET_VAR 'p0: kotlin.Int declared in <root>.Host.testBoundReceiverExpression.withVararg' type=kotlin.Int origin=null
             FUNCTION_REFERENCE 'local final fun withVararg (p0: kotlin.Int): kotlin.Unit declared in <root>.Host.testBoundReceiverExpression' type=kotlin.Function1<kotlin.Int, kotlin.Unit> origin=ADAPTED_FUNCTION_REFERENCE reflectionTarget=null
-              $receiver: GET_VAR 'val tmp_1: <root>.Host [val] declared in <root>.Host.testBoundReceiverExpression' type=<root>.Host origin=null
+              $receiver: CONSTRUCTOR_CALL 'public constructor <init> () [primary] declared in <root>.Host' type=<root>.Host origin=null
     FUN FAKE_OVERRIDE name:equals visibility:public modality:OPEN <> ($this:kotlin.Any, other:kotlin.Any?) returnType:kotlin.Boolean [fake_override,operator]
       overridden:
         public open fun equals (other: kotlin.Any?): kotlin.Boolean [operator] declared in kotlin.Any