From fe4a25eba1894e155464df597a50c909e0abf7a2 Mon Sep 17 00:00:00 2001
From: Roman Artemev <roman.artemev@jetbrains.com>
Date: Tue, 21 Sep 2021 13:08:51 +0700
Subject: [PATCH] [JS IR] Use context-dependent names for lambdas

Partially fix KT-46525

Now the code like
```
fun foo(a: () -> Unit) {}
interface A {
    fun run()
}
fun main() {
    foo {
        println()
    }
    val a = object : A {
        override fun run() {
            TODO()
        }
    }
}
```

is being compiled into

```
  function foo(a) {
  }
  function A() {
  }
  A.$metadata$ = {
    simpleName: 'A',
    kind: 'interface',
    interfaces: []
  };
  function main() {
    foo(main$lambda());
    var a = new _no_name_provided_();
  }
  function main$lambda() {
    return function () {
      println();
    };
  }

  // TODO
  function _no_name_provided_() {
  }
  _no_name_provided_.$metadata$ = {
    kind: 'class',
    interfaces: [A]
  };
```
---
 .../js/lower/CallableReferenceLowering.kt     | 37 ++++++++++++++++++-
 .../lower/InteropCallableReferenceLowering.kt |  4 +-
 2 files changed, 37 insertions(+), 4 deletions(-)

diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/CallableReferenceLowering.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/CallableReferenceLowering.kt
index 91e02b6bc71..38667b7db1e 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/CallableReferenceLowering.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/CallableReferenceLowering.kt
@@ -123,6 +123,41 @@ class CallableReferenceLowering(private val context: CommonBackendContext) : Bod
         private val superFunctionInterface = reference.type.classOrNull?.owner ?: error("Expected functional type")
         private val isKReference = superFunctionInterface.name.identifier[0] == 'K'
 
+        private fun StringBuilder.collectNamesForLambda(d: IrDeclarationWithName) {
+            val parent = d.parent
+
+            if (parent is IrPackageFragment) {
+                append(d.name.asString())
+                return
+            }
+
+            collectNamesForLambda(parent as IrDeclarationWithName)
+
+            if (d is IrAnonymousInitializer) return
+
+            fun IrDeclaration.isLambdaFun(): Boolean = origin == IrDeclarationOrigin.LOCAL_FUNCTION_FOR_LAMBDA
+
+            when {
+                d.isLambdaFun() -> {
+                    append('$')
+                    if (d is IrSimpleFunction && d.isSuspend) append('s')
+                    append("lambda")
+                }
+                d.name == SpecialNames.NO_NAME_PROVIDED -> append("\$o")
+                else -> {
+                    append('$')
+                    append(d.name.asString())
+                }
+            }
+        }
+
+        private fun makeContextDependentName(): Name {
+            val sb = StringBuilder()
+            sb.collectNamesForLambda(function)
+            if (!isLambda) sb.append("\$ref")
+            return Name.identifier(sb.toString())
+        }
+
         private fun buildReferenceClass(): IrClass {
             return context.irFactory.buildClass {
                 setSourceRange(reference)
@@ -130,7 +165,7 @@ class CallableReferenceLowering(private val context: CommonBackendContext) : Bod
                 // A callable reference results in a synthetic class, while a lambda is not synthetic.
                 // We don't produce GENERATED_SAM_IMPLEMENTATION, which is always synthetic.
                 origin = if (isKReference || !isLambda) FUNCTION_REFERENCE_IMPL else LAMBDA_IMPL
-                name = SpecialNames.NO_NAME_PROVIDED
+                name = makeContextDependentName()
             }.apply {
                 superTypes = listOf(superClass, reference.type)
 //                if (samSuperType == null)
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/InteropCallableReferenceLowering.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/InteropCallableReferenceLowering.kt
index b033358857d..7690183912b 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/InteropCallableReferenceLowering.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/InteropCallableReferenceLowering.kt
@@ -323,14 +323,12 @@ class InteropCallableReferenceLowering(val context: JsIrBackendContext) : BodyLo
         val newDeclarations = mutableListOf<IrDeclaration>()
         val constructor = lambdaClass.declarations.single { it is IrConstructor } as IrConstructor
 
-        val factoryName = Name.identifier("${lambdaClass.name.asString()}\$factory")
-
         val factoryDeclaration = context.irFactory.buildFun {
             startOffset = lambdaClass.startOffset
             endOffset = lambdaClass.endOffset
             visibility = lambdaClass.visibility
             returnType = lambdaClass.defaultType
-            name = factoryName
+            name = lambdaClass.name
             origin = JsStatementOrigins.FACTORY_ORIGIN
         }