From d6bc309c9405e32f9efaf91cd0283c0b55744739 Mon Sep 17 00:00:00 2001
From: Ilya Goncharov <ilya.goncharov@jetbrains.com>
Date: Mon, 9 Nov 2020 15:30:37 +0300
Subject: [PATCH] [JS IR] Eager initialisation for all pure properties

^KT-43222 fixed
---
 .../js/lower/PropertyLazyInitLowering.kt       |  9 ++++++++-
 .../box/properties/lazyInitializationPure.kt   | 18 ++++++++++++++++++
 .../IrJsCodegenBoxES6TestGenerated.java        |  5 +++++
 .../semantics/IrJsCodegenBoxTestGenerated.java |  5 +++++
 4 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 compiler/testData/codegen/box/properties/lazyInitializationPure.kt

diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/PropertyLazyInitLowering.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/PropertyLazyInitLowering.kt
index d35ee5020aa..92b60ceeb3f 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/PropertyLazyInitLowering.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/PropertyLazyInitLowering.kt
@@ -40,7 +40,14 @@ class PropertyLazyInitLowering(private val context: JsIrBackendContext) : FileLo
 
         val fieldToInitializer = calculateFieldToExpression(
             functions
-        ).onEach { it.key.initializer = null }
+        )
+
+        val allPropertyInitializersPure = fieldToInitializer
+            .all { it.value.isPure(anyVariable = true) }
+
+        if (allPropertyInitializersPure) return
+
+        fieldToInitializer.onEach { it.key.initializer = null }
 
         if (fieldToInitializer.isEmpty()) return
 
diff --git a/compiler/testData/codegen/box/properties/lazyInitializationPure.kt b/compiler/testData/codegen/box/properties/lazyInitializationPure.kt
new file mode 100644
index 00000000000..b08db6acaca
--- /dev/null
+++ b/compiler/testData/codegen/box/properties/lazyInitializationPure.kt
@@ -0,0 +1,18 @@
+// TARGET_BACKEND: JS_IR
+
+// FILE: A.kt
+
+val a = "A"
+
+// FILE: B.kt
+val b = "B".apply {}
+
+val c = "C"
+
+// FILE: main.kt
+
+fun box(): String {
+    return if (js("a") == "A" && js("typeof b") == "undefined" && js("typeof c") == "undefined")
+        "OK"
+    else "fail"
+}
\ No newline at end of file
diff --git a/js/js.tests/test/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java b/js/js.tests/test/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java
index af5fc5832c2..c18bbfc6bb2 100644
--- a/js/js.tests/test/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java
+++ b/js/js.tests/test/org/jetbrains/kotlin/js/test/es6/semantics/IrJsCodegenBoxES6TestGenerated.java
@@ -17634,6 +17634,11 @@ public class IrJsCodegenBoxES6TestGenerated extends AbstractIrJsCodegenBoxES6Tes
             runTest("compiler/testData/codegen/box/properties/lazyInitialization.kt");
         }
 
+        @TestMetadata("lazyInitializationPure.kt")
+        public void testLazyInitializationPure() throws Exception {
+            runTest("compiler/testData/codegen/box/properties/lazyInitializationPure.kt");
+        }
+
         @TestMetadata("primitiveOverrideDefaultAccessor.kt")
         public void testPrimitiveOverrideDefaultAccessor() throws Exception {
             runTest("compiler/testData/codegen/box/properties/primitiveOverrideDefaultAccessor.kt");
diff --git a/js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java b/js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java
index 79efbd55ec9..c1200b0aa20 100644
--- a/js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java
+++ b/js/js.tests/test/org/jetbrains/kotlin/js/test/ir/semantics/IrJsCodegenBoxTestGenerated.java
@@ -17634,6 +17634,11 @@ public class IrJsCodegenBoxTestGenerated extends AbstractIrJsCodegenBoxTest {
             runTest("compiler/testData/codegen/box/properties/lazyInitialization.kt");
         }
 
+        @TestMetadata("lazyInitializationPure.kt")
+        public void testLazyInitializationPure() throws Exception {
+            runTest("compiler/testData/codegen/box/properties/lazyInitializationPure.kt");
+        }
+
         @TestMetadata("primitiveOverrideDefaultAccessor.kt")
         public void testPrimitiveOverrideDefaultAccessor() throws Exception {
             runTest("compiler/testData/codegen/box/properties/primitiveOverrideDefaultAccessor.kt");