Unit obtained through a generic substitution should not be mapped to VOID

compiler/backend/src/org/jetbrains/jet/codegen/state/JetTypeMapper.java

@@ -159,7 +159,9 @@ public class JetTypeMapper {
     private Type mapReturnType(@NotNull CallableDescriptor descriptor, @Nullable BothSignatureWriter sw) {
         JetType returnType = descriptor.getReturnType();
         assert returnType != null : "Function has no return type: " + descriptor;
-        if (returnType.equals(KotlinBuiltIns.getInstance().getUnitType()) && !(descriptor instanceof PropertyGetterDescriptor)) {
+        if (returnType.equals(KotlinBuiltIns.getInstance().getUnitType())
+            && !TypeUtils.isNullableType(returnType)
+            && !(descriptor instanceof PropertyGetterDescriptor)) {
             if (sw != null) {
                 sw.writeAsmType(Type.VOID_TYPE);
             }

compiler/testData/codegen/boxAgainstJava/platformTypes/GenericUnit.java

@@ -0,0 +1,11 @@
+public class GenericUnit {
+    public static class Key<T> {}
+
+    public static <T> T getNull(Key<T> key) {
+        return null;
+    }
+
+    public static <T> T get(Key<T> key, T t) {
+        return t;
+    }
+}

compiler/testData/codegen/boxAgainstJava/platformTypes/GenericUnit.kt

@@ -0,0 +1,17 @@
+import GenericUnit.*
+
+val key = Key<Unit>()
+
+fun box(): String {
+    val n1 = getNull(key)
+    if (n1 != null) return "Fail 1: $n1"
+
+    val n2 = get(key, null)
+    if (n2 != null) return "Fail 2: $n2"
+
+    val n3 = get(key, Unit)
+    if (n3 == null) return "Fail 3.0: $n3"
+    if (n3 != Unit) return "Fail 3.1: $n3"
+
+    return "OK"
+}

compiler/tests/org/jetbrains/jet/codegen/generated/BlackBoxAgainstJavaCodegenTestGenerated.java

@@ -32,7 +32,7 @@ import java.util.regex.Pattern;
 @SuppressWarnings("all")
 @TestMetadata("compiler/testData/codegen/boxAgainstJava")
 @TestDataPath("$PROJECT_ROOT")
-@InnerTestClasses({BlackBoxAgainstJavaCodegenTestGenerated.Annotations.class, BlackBoxAgainstJavaCodegenTestGenerated.CallableReference.class, BlackBoxAgainstJavaCodegenTestGenerated.Constructor.class, BlackBoxAgainstJavaCodegenTestGenerated.Delegation.class, BlackBoxAgainstJavaCodegenTestGenerated.Enum.class, BlackBoxAgainstJavaCodegenTestGenerated.Functions.class, BlackBoxAgainstJavaCodegenTestGenerated.InnerClass.class, BlackBoxAgainstJavaCodegenTestGenerated.NotNullAssertions.class, BlackBoxAgainstJavaCodegenTestGenerated.Property.class, BlackBoxAgainstJavaCodegenTestGenerated.Reflection.class, BlackBoxAgainstJavaCodegenTestGenerated.Sam.class, BlackBoxAgainstJavaCodegenTestGenerated.StaticFun.class, BlackBoxAgainstJavaCodegenTestGenerated.Visibility.class})
+@InnerTestClasses({BlackBoxAgainstJavaCodegenTestGenerated.Annotations.class, BlackBoxAgainstJavaCodegenTestGenerated.CallableReference.class, BlackBoxAgainstJavaCodegenTestGenerated.Constructor.class, BlackBoxAgainstJavaCodegenTestGenerated.Delegation.class, BlackBoxAgainstJavaCodegenTestGenerated.Enum.class, BlackBoxAgainstJavaCodegenTestGenerated.Functions.class, BlackBoxAgainstJavaCodegenTestGenerated.InnerClass.class, BlackBoxAgainstJavaCodegenTestGenerated.NotNullAssertions.class, BlackBoxAgainstJavaCodegenTestGenerated.PlatformTypes.class, BlackBoxAgainstJavaCodegenTestGenerated.Property.class, BlackBoxAgainstJavaCodegenTestGenerated.Reflection.class, BlackBoxAgainstJavaCodegenTestGenerated.Sam.class, BlackBoxAgainstJavaCodegenTestGenerated.StaticFun.class, BlackBoxAgainstJavaCodegenTestGenerated.Visibility.class})
 @RunWith(org.jetbrains.jet.JUnit3RunnerWithInners.class)
 public class BlackBoxAgainstJavaCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
     public void testAllFilesPresentInBoxAgainstJava() throws Exception {
@@ -281,6 +281,22 @@ public class BlackBoxAgainstJavaCodegenTestGenerated extends AbstractBlackBoxCod
         
     }
     
+    @TestMetadata("compiler/testData/codegen/boxAgainstJava/platformTypes")
+    @TestDataPath("$PROJECT_ROOT")
+    @RunWith(org.jetbrains.jet.JUnit3RunnerWithInners.class)
+    public static class PlatformTypes extends AbstractBlackBoxCodegenTest {
+        public void testAllFilesPresentInPlatformTypes() throws Exception {
+            JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/codegen/boxAgainstJava/platformTypes"), Pattern.compile("^(.+)\\.kt$"), true);
+        }
+        
+        @TestMetadata("GenericUnit.kt")
+        public void testGenericUnit() throws Exception {
+            String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/boxAgainstJava/platformTypes/GenericUnit.kt");
+            doTestAgainstJava(fileName);
+        }
+        
+    }
+    
     @TestMetadata("compiler/testData/codegen/boxAgainstJava/property")
     @TestDataPath("$PROJECT_ROOT")
     @RunWith(org.jetbrains.jet.JUnit3RunnerWithInners.class)