From 06b6477d044d10779f68189909ed76346e97f78c Mon Sep 17 00:00:00 2001
From: Mark Punzalan <markpun@google.com>
Date: Wed, 5 Feb 2020 14:48:58 -0800
Subject: [PATCH] [JVM IR] Do not add nullability annotation for functions that
 return platform types.

This behavior matches the non-IR backend, which was added in
f16dcdd8a904c88eda90e9e5c620370dd1274298.
---
 .../kotlin/backend/jvm/codegen/AnnotationCodegen.kt  | 12 ++++++++----
 .../codegen/bytecodeListing/platformTypes.kt         |  8 ++++++++
 .../codegen/bytecodeListing/platformTypes.txt        |  7 +++++++
 .../kotlin/codegen/BytecodeListingTestGenerated.java |  5 +++++
 4 files changed, 28 insertions(+), 4 deletions(-)
 create mode 100644 compiler/testData/codegen/bytecodeListing/platformTypes.kt
 create mode 100644 compiler/testData/codegen/bytecodeListing/platformTypes.txt

diff --git a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/AnnotationCodegen.kt b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/AnnotationCodegen.kt
index 8f15a6c086b..4e4ee1fb36c 100644
--- a/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/AnnotationCodegen.kt
+++ b/compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/codegen/AnnotationCodegen.kt
@@ -32,10 +32,8 @@ import org.jetbrains.kotlin.descriptors.annotations.KotlinRetention
 import org.jetbrains.kotlin.descriptors.annotations.KotlinTarget
 import org.jetbrains.kotlin.ir.declarations.*
 import org.jetbrains.kotlin.ir.expressions.*
-import org.jetbrains.kotlin.ir.types.IrType
-import org.jetbrains.kotlin.ir.types.classifierOrNull
-import org.jetbrains.kotlin.ir.types.isMarkedNullable
-import org.jetbrains.kotlin.ir.types.isNullable
+import org.jetbrains.kotlin.ir.types.*
+import org.jetbrains.kotlin.ir.types.impl.originalKotlinType
 import org.jetbrains.kotlin.ir.util.*
 import org.jetbrains.kotlin.load.kotlin.FileBasedKotlinClass
 import org.jetbrains.kotlin.load.kotlin.KotlinJvmBinarySourceElement
@@ -45,6 +43,7 @@ import org.jetbrains.kotlin.resolve.checkers.ExpectedActualDeclarationChecker
 import org.jetbrains.kotlin.serialization.deserialization.descriptors.DeserializedClassDescriptor
 import org.jetbrains.kotlin.synthetic.isVisibleOutside
 import org.jetbrains.kotlin.types.TypeSystemCommonBackendContext
+import org.jetbrains.kotlin.types.isNullabilityFlexible
 import org.jetbrains.kotlin.types.model.KotlinTypeMarker
 import org.jetbrains.org.objectweb.asm.*
 import java.lang.annotation.RetentionPolicy
@@ -153,6 +152,11 @@ abstract class AnnotationCodegen(
             return
         }
 
+        // A flexible type whose lower bound in not-null and upper bound is nullable, should not be annotated
+        if (type.toKotlinType().isNullabilityFlexible()) {
+            return
+        }
+
         val annotationClass = if (type.isNullable()) Nullable::class.java else NotNull::class.java
 
         generateAnnotationIfNotPresent(annotationDescriptorsAlreadyPresent, annotationClass)
diff --git a/compiler/testData/codegen/bytecodeListing/platformTypes.kt b/compiler/testData/codegen/bytecodeListing/platformTypes.kt
new file mode 100644
index 00000000000..4fc6b8e00b7
--- /dev/null
+++ b/compiler/testData/codegen/bytecodeListing/platformTypes.kt
@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+import java.util.Collections
+
+class PlatformTypes {
+    fun simplyPlatform() = Collections.singletonList("")[0]
+    fun bothNullable() = Collections.emptyList<String>() ?: null
+    fun bothNotNull() = Collections.emptyList<String>()!!
+}
diff --git a/compiler/testData/codegen/bytecodeListing/platformTypes.txt b/compiler/testData/codegen/bytecodeListing/platformTypes.txt
new file mode 100644
index 00000000000..b4308ab326d
--- /dev/null
+++ b/compiler/testData/codegen/bytecodeListing/platformTypes.txt
@@ -0,0 +1,7 @@
+@kotlin.Metadata
+public final class PlatformTypes {
+    public method <init>(): void
+    public final @org.jetbrains.annotations.NotNull method bothNotNull(): java.util.List
+    public final @org.jetbrains.annotations.Nullable method bothNullable(): java.util.List
+    public final method simplyPlatform(): java.lang.String
+}
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/BytecodeListingTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/codegen/BytecodeListingTestGenerated.java
index 1b980011637..983b2b85fad 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/BytecodeListingTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/BytecodeListingTestGenerated.java
@@ -94,6 +94,11 @@ public class BytecodeListingTestGenerated extends AbstractBytecodeListingTest {
         runTest("compiler/testData/codegen/bytecodeListing/noToArrayInJava.kt");
     }
 
+    @TestMetadata("platformTypes.kt")
+    public void testPlatformTypes() throws Exception {
+        runTest("compiler/testData/codegen/bytecodeListing/platformTypes.kt");
+    }
+
     @TestMetadata("privateDefaultSetter.kt")
     public void testPrivateDefaultSetter() throws Exception {
         runTest("compiler/testData/codegen/bytecodeListing/privateDefaultSetter.kt");