From 5e5712afbb543b4e8221b63463f277658ceee9e2 Mon Sep 17 00:00:00 2001
From: Svyatoslav Kuzmich <svyatoslav.kuzmich@jetbrains.com>
Date: Wed, 7 Oct 2020 08:38:27 +0300
Subject: [PATCH] [JS IR] Make JsExport not fail on companion objects
 (KT-37829)

---
 .../ir/backend/js/export/ExportModelGenerator.kt       |  7 +++++--
 .../kotlin/ir/backend/js/lower/ObjectLowering.kt       |  6 ++----
 .../typescript-export/declarations/declarations.d.ts   |  6 ++++++
 .../typescript-export/declarations/declarations.kt     | 10 +++++++++-
 4 files changed, 22 insertions(+), 7 deletions(-)

diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/export/ExportModelGenerator.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/export/ExportModelGenerator.kt
index 69c0b9bb9bb..1bb08d7037c 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/export/ExportModelGenerator.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/export/ExportModelGenerator.kt
@@ -171,8 +171,11 @@ class ExportModelGenerator(val context: JsIrBackendContext) {
                 }
 
                 is IrField -> {
-                    assert(candidate.correspondingPropertySymbol != null) {
-                        "Properties without fields are not supported ${candidate.fqNameWhenAvailable}"
+                    assert(
+                        candidate.origin == IrDeclarationOrigin.FIELD_FOR_OBJECT_INSTANCE
+                                || candidate.correspondingPropertySymbol != null
+                    ) {
+                        "Unexpected field without property ${candidate.fqNameWhenAvailable}"
                     }
                 }
 
diff --git a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/ObjectLowering.kt b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/ObjectLowering.kt
index 778b71d466c..8627aac6678 100644
--- a/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/ObjectLowering.kt
+++ b/compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/lower/ObjectLowering.kt
@@ -19,10 +19,7 @@ import org.jetbrains.kotlin.ir.backend.js.ir.JsIrBuilder
 import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.builders.declarations.buildField
 import org.jetbrains.kotlin.ir.builders.declarations.buildFun
-import org.jetbrains.kotlin.ir.declarations.IrClass
-import org.jetbrains.kotlin.ir.declarations.IrConstructor
-import org.jetbrains.kotlin.ir.declarations.IrDeclaration
-import org.jetbrains.kotlin.ir.declarations.IrVariable
+import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.expressions.*
 import org.jetbrains.kotlin.ir.types.makeNullable
 import org.jetbrains.kotlin.ir.util.*
@@ -47,6 +44,7 @@ class ObjectDeclarationLowering(
             name = Name.identifier(declaration.name.asString() + "_instance")
             type = declaration.defaultType.makeNullable()
             isStatic = true
+            origin = IrDeclarationOrigin.FIELD_FOR_OBJECT_INSTANCE
         }.apply {
             parent = declaration.parent
             initializer = null  // Initialized with 'undefined'
diff --git a/js/js.translator/testData/typescript-export/declarations/declarations.d.ts b/js/js.translator/testData/typescript-export/declarations/declarations.d.ts
index 0d6dd8172ae..b651642ea2c 100644
--- a/js/js.translator/testData/typescript-export/declarations/declarations.d.ts
+++ b/js/js.translator/testData/typescript-export/declarations/declarations.d.ts
@@ -49,5 +49,11 @@ declare namespace JS_TESTS {
             foo(): number;
         };
         function takesO(o: typeof foo.O): number;
+        class KT_37829 {
+            constructor();
+            readonly Companion: {
+                readonly x: number;
+            };
+        }
     }
 }
diff --git a/js/js.translator/testData/typescript-export/declarations/declarations.kt b/js/js.translator/testData/typescript-export/declarations/declarations.kt
index 67955083651..6a46ee46f5e 100644
--- a/js/js.translator/testData/typescript-export/declarations/declarations.kt
+++ b/js/js.translator/testData/typescript-export/declarations/declarations.kt
@@ -93,4 +93,12 @@ object O {
 }
 
 fun takesO(o: O): Int =
-    O.x + O.foo()
\ No newline at end of file
+    O.x + O.foo()
+
+// Test that JsExport with companion object compiles without error.
+// Usage is not supported yet.
+class KT_37829 {
+    companion object {
+        val x = 10
+    }
+}
\ No newline at end of file