From d09be811f005464285df6833ed323d4dec583aa8 Mon Sep 17 00:00:00 2001
From: Tianyu Geng <tgeng@google.com>
Date: Thu, 22 Apr 2021 14:56:43 -0700
Subject: [PATCH] FIR: make class delegation field a fake source

Previously, the FirFieldImpl generated from class delegation has a real
source. This causes troubles in the IDE. This change adds a new fake
source kind for class delegation fields.
---
 .../kotlin/fir/lightTree/converter/DeclarationsConverter.kt   | 2 +-
 .../src/org/jetbrains/kotlin/fir/builder/RawFirBuilder.kt     | 3 ++-
 .../fir/tree/src/org/jetbrains/kotlin/fir/FirSourceElement.kt | 4 ++++
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/compiler/fir/raw-fir/light-tree2fir/src/org/jetbrains/kotlin/fir/lightTree/converter/DeclarationsConverter.kt b/compiler/fir/raw-fir/light-tree2fir/src/org/jetbrains/kotlin/fir/lightTree/converter/DeclarationsConverter.kt
index 60fee0ab6ab..69a9082dbee 100644
--- a/compiler/fir/raw-fir/light-tree2fir/src/org/jetbrains/kotlin/fir/lightTree/converter/DeclarationsConverter.kt
+++ b/compiler/fir/raw-fir/light-tree2fir/src/org/jetbrains/kotlin/fir/lightTree/converter/DeclarationsConverter.kt
@@ -1574,7 +1574,7 @@ class DeclarationsConverter(
         val delegateName = Name.special("<\$\$delegate_${delegateFields.size}>")
         delegateFields.add(
             buildField {
-                source = firExpression!!.source
+                source = firExpression!!.source?.fakeElement(FirFakeSourceElementKind.ClassDelegationField)
                 declarationSiteSession = baseSession
                 origin = FirDeclarationOrigin.Synthetic
                 name = delegateName
diff --git a/compiler/fir/raw-fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/RawFirBuilder.kt b/compiler/fir/raw-fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/RawFirBuilder.kt
index 99f4c665aff..3594f8185bd 100644
--- a/compiler/fir/raw-fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/RawFirBuilder.kt
+++ b/compiler/fir/raw-fir/psi2fir/src/org/jetbrains/kotlin/fir/builder/RawFirBuilder.kt
@@ -566,7 +566,8 @@ open class RawFirBuilder(
                         val delegateExpression = { superTypeListEntry.delegateExpression }.toFirExpression("Should have delegate")
                         container.superTypeRefs += type
                         val delegateName = Name.special("<\$\$delegate_${delegateFields.size}>")
-                        val delegateSource = superTypeListEntry.delegateExpression?.toFirSourceElement()
+                        val delegateSource =
+                            superTypeListEntry.delegateExpression?.toFirSourceElement(FirFakeSourceElementKind.ClassDelegationField)
                         val delegateField = buildField {
                             source = delegateSource
                             declarationSiteSession = baseSession
diff --git a/compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirSourceElement.kt b/compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirSourceElement.kt
index 7c5b3ad2ac7..3217e74b7d5 100644
--- a/compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirSourceElement.kt
+++ b/compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirSourceElement.kt
@@ -170,6 +170,10 @@ sealed class FirFakeSourceElementKind : FirSourceElementKind() {
     // for java annotations constructor implicit parameters are generated
     // with a fake source which refers to declared annotation methods
     object ImplicitAnnotationAnnotationConstructorParameter : FirFakeSourceElementKind()
+
+    // for the implicit field storing the delegated object for class delegation
+    // with a fake source that refers to the KtExpression that creates the delegate
+    object ClassDelegationField : FirFakeSourceElementKind()
 }
 
 sealed class FirSourceElement {