FIR2IR: use elvis temporary variable name closer to PSI2IR

Related to KT-61983

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrConversionScope.kt

@@ -10,6 +10,7 @@ import org.jetbrains.kotlin.fir.declarations.FirConstructor
 import org.jetbrains.kotlin.fir.declarations.FirProperty
 import org.jetbrains.kotlin.fir.declarations.FirPropertyAccessor
 import org.jetbrains.kotlin.fir.expressions.FirReturnExpression
+import org.jetbrains.kotlin.ir.builders.Scope
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.symbols.IrClassSymbol
 import org.jetbrains.kotlin.ir.symbols.IrPropertySymbol
@@ -27,6 +28,10 @@ class Fir2IrConversionScope(val configuration: Fir2IrConfiguration) {
     @PrivateForInline
     internal val parentStack = mutableListOf<IrDeclarationParent>()
 
+    @PublishedApi
+    @PrivateForInline
+    internal val scopeStack = mutableListOf<Scope>()
+
     @PublishedApi
     @PrivateForInline
     internal val containingFirClassStack = mutableListOf<FirClass>()
@@ -37,9 +42,15 @@ class Fir2IrConversionScope(val configuration: Fir2IrConfiguration) {
 
     inline fun <T : IrDeclarationParent, R> withParent(parent: T, f: T.() -> R): R {
         parentStack += parent
+        if (parent is IrDeclaration) {
+            scopeStack += Scope(parent.symbol)
+        }
         try {
             return parent.f()
         } finally {
+            if (parent is IrDeclaration) {
+                scopeStack.removeAt(scopeStack.size - 1)
+            }
             parentStack.removeAt(parentStack.size - 1)
         }
     }
@@ -69,6 +80,8 @@ class Fir2IrConversionScope(val configuration: Fir2IrConfiguration) {
 
     fun parentFromStack(): IrDeclarationParent = parentStack.last()
 
+    fun scope(): Scope = scopeStack.last()
+
     fun parentAccessorOfPropertyFromStack(propertySymbol: IrPropertySymbol): IrSimpleFunction {
         // It is safe to access an owner of property symbol here, because this function may be called
         // only from property accessor of corresponding property

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrVisitor.kt

@@ -8,7 +8,6 @@ package org.jetbrains.kotlin.fir.backend
 import com.intellij.psi.tree.IElementType
 import org.jetbrains.kotlin.*
 import org.jetbrains.kotlin.contracts.description.LogicOperationKind
-import org.jetbrains.kotlin.descriptors.Modality
 import org.jetbrains.kotlin.descriptors.Visibilities
 import org.jetbrains.kotlin.descriptors.isObject
 import org.jetbrains.kotlin.diagnostics.findChildByType
@@ -16,8 +15,6 @@ import org.jetbrains.kotlin.fir.*
 import org.jetbrains.kotlin.fir.backend.generators.ClassMemberGenerator
 import org.jetbrains.kotlin.fir.backend.generators.OperatorExpressionGenerator
 import org.jetbrains.kotlin.fir.declarations.*
-import org.jetbrains.kotlin.fir.declarations.builder.buildProperty
-import org.jetbrains.kotlin.fir.declarations.impl.FirDeclarationStatusImpl
 import org.jetbrains.kotlin.fir.declarations.utils.*
 import org.jetbrains.kotlin.fir.deserialization.toQualifiedPropertyAccessExpression
 import org.jetbrains.kotlin.fir.expressions.*
@@ -1150,24 +1147,18 @@ class Fir2IrVisitor(
     }
 
     override fun visitElvisExpression(elvisExpression: FirElvisExpression, data: Any?): IrElement {
-        val firLhsVariable = buildProperty {
-            source = elvisExpression.source
-            moduleData = session.moduleData
-            origin = FirDeclarationOrigin.Source
-            returnTypeRef = elvisExpression.lhs.resolvedType.toFirResolvedTypeRef()
-            name = Name.special("<elvis>")
-            initializer = elvisExpression.lhs
-            symbol = FirPropertySymbol(name)
-            isVar = false
-            isLocal = true
-            status = FirDeclarationStatusImpl(Visibilities.Local, Modality.FINAL)
-        }
-        val irLhsVariable = firLhsVariable.accept(this, null) as IrVariable
         return elvisExpression.convertWithOffsets { startOffset, endOffset ->
+            val irLhsVariable = conversionScope.scope().createTemporaryVariable(
+                irExpression = elvisExpression.lhs.accept(this, null) as IrExpression,
+                nameHint = "elvis_lhs",
+                startOffset = startOffset,
+                endOffset = endOffset
+            )
+
             fun irGetLhsValue(): IrGetValue =
                 IrGetValueImpl(startOffset, endOffset, irLhsVariable.type, irLhsVariable.symbol)
 
-            val originalType = firLhsVariable.returnTypeRef.coneType
+            val originalType = elvisExpression.lhs.resolvedType
             val notNullType = originalType.withNullability(ConeNullability.NOT_NULL, session.typeContext)
             val irBranches = listOf(
                 IrBranchImpl(
@@ -1188,7 +1179,7 @@ class Fir2IrVisitor(
                     } else {
                         Fir2IrImplicitCastInserter.implicitCastOrExpression(
                             irGetLhsValue(),
-                            firLhsVariable.returnTypeRef.resolvedTypeFromPrototype(notNullType).toIrType()
+                            originalType.toFirResolvedTypeRef().resolvedTypeFromPrototype(notNullType).toIrType()
                         )
                     }
                 )

compiler/testData/ir/sourceRanges/elvis.fir.txt

@@ -1,20 +0,0 @@
-@0:0..3:0 FILE fqName:<root> fileName:/elvis.kt
-  @0:0..23 FUN name:intN visibility:public modality:FINAL <> () returnType:kotlin.Int?
-    @0:19..23 BLOCK_BODY
-      @0:23..23 RETURN type=kotlin.Nothing from='public final fun intN (): kotlin.Int? declared in <root>'
-        @0:19..23 CONST Null type=kotlin.Nothing? value=null
-  @2:0..24 FUN name:test visibility:public modality:FINAL <> () returnType:kotlin.Int
-    @2:13..24 BLOCK_BODY
-      @2:24..24 RETURN type=kotlin.Nothing from='public final fun test (): kotlin.Int declared in <root>'
-        @2:13..24 BLOCK type=kotlin.Int origin=ELVIS
-          @2:13..24 VAR IR_TEMPORARY_VARIABLE name:<elvis> type:kotlin.Int? [val]
-            @2:13..19 CALL 'public final fun intN (): kotlin.Int? declared in <root>' type=kotlin.Int? origin=null
-          @2:13..24 WHEN type=kotlin.Int origin=null
-            @2:13..24 BRANCH
-              @2:13..24 CALL 'public final fun EQEQ (arg0: kotlin.Any?, arg1: kotlin.Any?): kotlin.Boolean declared in kotlin.internal.ir' type=kotlin.Boolean origin=EQEQ
-                @2:13..24 GET_VAR 'val <elvis>: kotlin.Int? [val] declared in <root>.test' type=kotlin.Int? origin=null
-                @2:13..24 CONST Null type=kotlin.Nothing? value=null
-              @2:23..24 CONST Int type=kotlin.Int value=1
-            @2:13..24 BRANCH
-              @2:13..24 CONST Boolean type=kotlin.Boolean value=true
-              @2:13..24 GET_VAR 'val <elvis>: kotlin.Int? [val] declared in <root>.test' type=kotlin.Int? origin=null

compiler/testData/ir/sourceRanges/elvis.kt

@@ -1,3 +1,5 @@
 fun intN(): Int? = null
 
 fun test() = intN() ?: 1
+
+// FIR_IDENTICAL

compiler/testData/ir/sourceRanges/elvis.txt

@@ -1,4 +1,4 @@
-@0:0..3:0 FILE fqName:<root> fileName:/elvis.kt
+@0:0..5:0 FILE fqName:<root> fileName:/elvis.kt
   @0:0..23 FUN name:intN visibility:public modality:FINAL <> () returnType:kotlin.Int?
     @0:19..23 BLOCK_BODY
       @0:23..23 RETURN type=kotlin.Nothing from='public final fun intN (): kotlin.Int? declared in <root>'

js/js.translator/testData/box/jsAstOptimizations/deadCodeElimination.kt

@@ -1,6 +1,3 @@
-// IGNORE_BACKEND_K2: JS_IR, JS_IR_ES6
-// FIR works fine, however it generates another names for the temporary variables, therefore ignore it
-
 fun demo(f: () -> String) = f()
 
 // EXPECT_GENERATED_JS: function=test$lambda expect=deadCodeEliminationTestLambda.js