Generate proper initialization for possibly nullable SAM wrapper

#KT-18916 Fixed Target versions 1.1.5

compiler/backend/src/org/jetbrains/kotlin/codegen/ExpressionCodegen.java

@@ -2048,32 +2048,27 @@ public class ExpressionCodegen extends KtVisitor<StackValue, StackValue> impleme
             return genClosure((KtNamedFunction) expression, samType);
         }
 
-        Type asmType =
-                state.getSamWrapperClasses().getSamWrapperClass(samType, expression.getContainingKtFile(), this);
+        Type asmType = state.getSamWrapperClasses().getSamWrapperClass(samType, expression.getContainingKtFile(), this);
 
         return StackValue.operation(asmType, v -> {
-            v.anew(asmType);
-            v.dup();
+            Label afterAll = new Label();
 
             Type functionType = typeMapper.mapType(samType.getKotlinFunctionType());
             expression.accept(visitor, StackValue.none()).put(functionType, v);
 
-            Label ifNonNull = new Label();
-            Label afterAll = new Label();
-
             v.dup();
-            v.ifnonnull(ifNonNull);
+            v.ifnull(afterAll);
 
-            // if null: pop function value and wrapper objects, put null
-            v.pop();
-            v.pop2();
-            v.aconst(null);
-            v.goTo(afterAll);
-
-            v.mark(ifNonNull);
+            int tmp = myFrameMap.enterTemp(functionType);
+            v.store(tmp, functionType);
+            v.anew(asmType);
+            v.dup();
+            v.load(tmp, functionType);
             v.invokespecial(asmType.getInternalName(), "<init>", Type.getMethodDescriptor(Type.VOID_TYPE, functionType), false);
+            myFrameMap.leaveTemp(functionType);
 
             v.mark(afterAll);
+
             return null;
         });
     }

compiler/testData/codegen/bytecodeText/sam/samWrapperForNullInitialization.kt

@@ -0,0 +1,26 @@
+// WITH_RUNTIME
+// FILE: JFoo.java
+
+import org.jetbrains.annotations.Nullable;
+
+public class JFoo {
+    public static void foo2(@Nullable Runnable h1, @Nullable Runnable h2) {
+        if (h2 != null) throw new AssertionError();
+        h1.run();
+    }
+}
+
+// FILE: Test.kt
+fun test() {
+    var i = 0
+    JFoo.foo2({ i++ }, null)
+}
+
+// @TestKt.class:
+// 1 NEW TestKt\$test\$1
+// 1 NEW kotlin/jvm/internal/Ref\$IntRef
+// 2 NEW
+// 1 INVOKESPECIAL TestKt\$test\$1.<init>
+// 0 IFNONNULL
+// 0 IFNULL
+// 1 ACONST_NULL

compiler/testData/codegen/bytecodeText/sam/samWrapperForNullableInitialization.kt

@@ -0,0 +1,24 @@
+// WITH_RUNTIME
+// FILE: JFoo.java
+
+import org.jetbrains.annotations.Nullable;
+
+public class JFoo {
+    public static void foo2(@Nullable Runnable h1, @Nullable Runnable h2) {
+        if (h2 != null) throw new AssertionError();
+        h1.run();
+    }
+}
+
+// FILE: Test.kt
+fun runnable(): (() -> Unit)? = null
+
+fun test() {
+    JFoo.foo2({}, runnable())
+}
+
+// @TestKt.class:
+// 2 NEW
+// 0 IFNONNULL
+// 1 IFNULL
+// 1 ACONST_NULL

compiler/tests/org/jetbrains/kotlin/codegen/BytecodeTextTestGenerated.java

@@ -1920,6 +1920,27 @@ public class BytecodeTextTestGenerated extends AbstractBytecodeTextTest {
         }
     }
 
+    @TestMetadata("compiler/testData/codegen/bytecodeText/sam")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(JUnit3RunnerWithInners.class)
+    public static class Sam extends AbstractBytecodeTextTest {
+        public void testAllFilesPresentInSam() throws Exception {
+            KotlinTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/codegen/bytecodeText/sam"), Pattern.compile("^(.+)\\.kt$"), TargetBackend.ANY, true);
+        }
+
+        @TestMetadata("samWrapperForNullInitialization.kt")
+        public void testSamWrapperForNullInitialization() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/bytecodeText/sam/samWrapperForNullInitialization.kt");
+            doTest(fileName);
+        }
+
+        @TestMetadata("samWrapperForNullableInitialization.kt")
+        public void testSamWrapperForNullableInitialization() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/codegen/bytecodeText/sam/samWrapperForNullableInitialization.kt");
+            doTest(fileName);
+        }
+    }
+
     @TestMetadata("compiler/testData/codegen/bytecodeText/statements")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(JUnit3RunnerWithInners.class)