IrFunctionExpression: add 'origin'

This is actually either a LAMBDA or an ANONYMOUS_FUNCTION.
Not quite sure if it's really required, but some tools such as IR-based
decompiler might require this information.

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

@@ -17,6 +17,7 @@
 package org.jetbrains.kotlin.psi2ir.generators
 
 import org.jetbrains.kotlin.ir.IrStatement
+import org.jetbrains.kotlin.ir.expressions.IrStatementOrigin
 import org.jetbrains.kotlin.ir.expressions.impl.IrFunctionExpressionImpl
 import org.jetbrains.kotlin.psi.KtLambdaExpression
 import org.jetbrains.kotlin.psi.KtNamedFunction
@@ -30,7 +31,12 @@ class LocalFunctionGenerator(statementGenerator: StatementGenerator) : Statement
         val lambdaExpressionType = getInferredTypeWithImplicitCastsOrFail(ktLambda).toIrType()
         val irLambdaFunction = FunctionGenerator(context).generateLambdaFunctionDeclaration(ktFun)
 
-        return IrFunctionExpressionImpl(ktLambda.startOffset, ktLambda.endOffset, lambdaExpressionType, irLambdaFunction)
+        return IrFunctionExpressionImpl(
+            ktLambda.startOffset, ktLambda.endOffset,
+            lambdaExpressionType,
+            irLambdaFunction,
+            IrStatementOrigin.LAMBDA
+        )
     }
 
     fun generateFunction(ktFun: KtNamedFunction): IrStatement {
@@ -38,7 +44,12 @@ class LocalFunctionGenerator(statementGenerator: StatementGenerator) : Statement
         if (ktFun.name != null) return irFun
 
         val funExpressionType = getInferredTypeWithImplicitCastsOrFail(ktFun).toIrType()
-        return IrFunctionExpressionImpl(ktFun.startOffset, ktFun.endOffset, funExpressionType, irFun)
+        return IrFunctionExpressionImpl(
+            ktFun.startOffset, ktFun.endOffset,
+            funExpressionType,
+            irFun,
+            IrStatementOrigin.ANONYMOUS_FUNCTION
+        )
     }
 
     private fun generateFunctionDeclaration(ktFun: KtNamedFunction) =

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/IrFunctionExpression.kt

@@ -8,7 +8,6 @@ package org.jetbrains.kotlin.ir.expressions
 import org.jetbrains.kotlin.ir.declarations.IrSimpleFunction
 
 interface IrFunctionExpression : IrExpression {
-
+    val origin: IrStatementOrigin
     var function: IrSimpleFunction
-
 }

compiler/ir/ir.tree/src/org/jetbrains/kotlin/ir/expressions/impl/IrFunctionExpressionImpl.kt

@@ -7,6 +7,7 @@ package org.jetbrains.kotlin.ir.expressions.impl
 
 import org.jetbrains.kotlin.ir.declarations.IrSimpleFunction
 import org.jetbrains.kotlin.ir.expressions.IrFunctionExpression
+import org.jetbrains.kotlin.ir.expressions.IrStatementOrigin
 import org.jetbrains.kotlin.ir.types.IrType
 import org.jetbrains.kotlin.ir.visitors.IrElementTransformer
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitor
@@ -15,7 +16,8 @@ class IrFunctionExpressionImpl(
     startOffset: Int,
     endOffset: Int,
     type: IrType,
-    override var function: IrSimpleFunction
+    override var function: IrSimpleFunction,
+    override val origin: IrStatementOrigin
 ) :
     IrExpressionBase(startOffset, endOffset, type),
     IrFunctionExpression {

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

@@ -593,7 +593,8 @@ open class DeepCopyIrTreeWithSymbols(
         IrFunctionExpressionImpl(
             expression.startOffset, expression.endOffset,
             expression.type.remapType(),
-            expression.function.transform()
+            expression.function.transform(),
+            mapStatementOrigin(expression.origin)!!
         )
 
     override fun visitClassReference(expression: IrClassReference): IrClassReference =

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

@@ -603,7 +603,7 @@ class RenderIrElementVisitor : IrElementVisitor<String, Nothing?> {
 
     override fun visitFunctionExpression(expression: IrFunctionExpression, data: Nothing?): String =
         buildTrimEnd {
-            append("FUN_EXPR type=${expression.type.render()}")
+            append("FUN_EXPR type=${expression.type.render()} origin=${expression.origin}")
         }
 
     override fun visitClassReference(expression: IrClassReference, data: Nothing?): String =