From a30d9e0ed3fd27acc8817075d682cebf833b85fd Mon Sep 17 00:00:00 2001
From: Ilya Kirillov <ilya.kirillov@jetbrains.com>
Date: Tue, 15 Dec 2020 20:26:23 +0100
Subject: [PATCH] FIR: add fake source fir element to `it` parameter symbol

---
 .../kotlin/fir/resolve/inference/FirCallCompleter.kt          | 4 +++-
 .../fir/tree/src/org/jetbrains/kotlin/fir/FirSourceElement.kt | 4 ++++
 .../kotlin/idea/fir/low/level/api/api/LowLevelFirApiFacade.kt | 3 ++-
 idea/testData/highlighter/AutoCreatedItParameter.kt           | 1 -
 4 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/FirCallCompleter.kt b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/FirCallCompleter.kt
index 217f86e2997..f3dc5091520 100644
--- a/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/FirCallCompleter.kt
+++ b/compiler/fir/resolve/src/org/jetbrains/kotlin/fir/resolve/inference/FirCallCompleter.kt
@@ -5,12 +5,14 @@
 
 package org.jetbrains.kotlin.fir.resolve.inference
 
+import org.jetbrains.kotlin.fir.FirFakeSourceElementKind
 import org.jetbrains.kotlin.fir.declarations.FirAnonymousFunction
 import org.jetbrains.kotlin.fir.declarations.FirDeclarationOrigin
 import org.jetbrains.kotlin.fir.declarations.builder.buildValueParameter
 import org.jetbrains.kotlin.fir.expressions.FirExpression
 import org.jetbrains.kotlin.fir.expressions.FirResolvable
 import org.jetbrains.kotlin.fir.expressions.FirStatement
+import org.jetbrains.kotlin.fir.fakeElement
 import org.jetbrains.kotlin.fir.resolve.ResolutionMode
 import org.jetbrains.kotlin.fir.resolve.calls.Candidate
 import org.jetbrains.kotlin.fir.resolve.calls.FirNamedReferenceWithCandidate
@@ -33,7 +35,6 @@ import org.jetbrains.kotlin.fir.visitors.transformSingle
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.calls.inference.buildAbstractResultingSubstitutor
 import org.jetbrains.kotlin.resolve.calls.inference.components.ConstraintSystemCompletionMode
-import org.jetbrains.kotlin.resolve.calls.inference.model.ArgumentConstraintPosition
 import org.jetbrains.kotlin.resolve.calls.inference.model.SimpleConstraintSystemConstraintPosition
 import org.jetbrains.kotlin.types.TypeApproximatorConfiguration
 import org.jetbrains.kotlin.types.model.StubTypeMarker
@@ -183,6 +184,7 @@ class FirCallCompleter(
                     val name = Name.identifier("it")
                     val itType = parameters.single()
                     buildValueParameter {
+                        source = lambdaAtom.atom.source?.fakeElement(FirFakeSourceElementKind.ItLambdaParameter)
                         session = this@FirCallCompleter.session
                         origin = FirDeclarationOrigin.Source
                         returnTypeRef = buildResolvedTypeRef { type = itType.approximateLambdaInputType() }
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 cc05f1bb283..bab6e154260 100644
--- a/compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirSourceElement.kt
+++ b/compiler/fir/tree/src/org/jetbrains/kotlin/fir/FirSourceElement.kt
@@ -157,6 +157,10 @@ sealed class FirFakeSourceElementKind : FirSourceElementKind() {
 
     // Part of desugared x?.y
     object CheckedSafeCallSubject : FirFakeSourceElementKind()
+
+    // { it + 1} --> { it -> it + 1 }
+    // where `it` parameter declaration has fake source
+    object ItLambdaParameter : FirFakeSourceElementKind()
 }
 
 sealed class FirSourceElement {
diff --git a/idea/idea-frontend-fir/idea-fir-low-level-api/src/org/jetbrains/kotlin/idea/fir/low/level/api/api/LowLevelFirApiFacade.kt b/idea/idea-frontend-fir/idea-fir-low-level-api/src/org/jetbrains/kotlin/idea/fir/low/level/api/api/LowLevelFirApiFacade.kt
index e51d168ec1f..13d6ac803a8 100644
--- a/idea/idea-frontend-fir/idea-fir-low-level-api/src/org/jetbrains/kotlin/idea/fir/low/level/api/api/LowLevelFirApiFacade.kt
+++ b/idea/idea-frontend-fir/idea-fir-low-level-api/src/org/jetbrains/kotlin/idea/fir/low/level/api/api/LowLevelFirApiFacade.kt
@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.idea.fir.low.level.api.api
 import org.jetbrains.kotlin.diagnostics.Diagnostic
 import org.jetbrains.kotlin.fir.FirElement
 import org.jetbrains.kotlin.fir.declarations.*
+import org.jetbrains.kotlin.fir.psi
 import org.jetbrains.kotlin.fir.render
 import org.jetbrains.kotlin.fir.unwrapFakeOverrides
 import org.jetbrains.kotlin.idea.caches.project.IdeaModuleInfo
@@ -109,7 +110,7 @@ fun <D : FirDeclaration, R> D.withFirDeclaration(
         -> {
             val cache = session.cache
             val file = resolveState.getFirFile(this, cache)
-                ?: error("Fir file was not found for\n${render()}\n${ktDeclaration.getElementTextInContext()}")
+                ?: error("Fir file was not found for\n${render()}\n${(psi as? KtElement)?.getElementTextInContext()}")
             cache.firFileLockProvider.withReadLock(file) { action(this) }
         }
         else -> action(this)
diff --git a/idea/testData/highlighter/AutoCreatedItParameter.kt b/idea/testData/highlighter/AutoCreatedItParameter.kt
index 68af0a13a90..f50f05c068b 100644
--- a/idea/testData/highlighter/AutoCreatedItParameter.kt
+++ b/idea/testData/highlighter/AutoCreatedItParameter.kt
@@ -1,4 +1,3 @@
-// IGNORE_FIR
 fun <info textAttributesKey="KOTLIN_FUNCTION_DECLARATION">test</info>() {
     val <info textAttributesKey="KOTLIN_LOCAL_VARIABLE">vect</info> = <info textAttributesKey="KOTLIN_CONSTRUCTOR">MyIterable</info><<info textAttributesKey="KOTLIN_CLASS">Int</info>>()
     <info textAttributesKey="KOTLIN_LOCAL_VARIABLE">vect</info>.<info textAttributesKey="KOTLIN_FUNCTION_CALL">filter</info> { <info textAttributesKey="KOTLIN_CLOSURE_DEFAULT_PARAMETER">it</info> != 2 }.<info textAttributesKey="KOTLIN_FUNCTION_CALL">forEach</info> { <info textAttributesKey="KOTLIN_CLOSURE_DEFAULT_PARAMETER">it</info>.<info textAttributesKey="KOTLIN_FUNCTION_CALL">toString</info>() }