Fix StackValue.coerce void to Object

We can only put Unit.VALUE on stack if we're requested an instance of Object or
Unit. In other cases (arbitrary objects / arrays) we put null instead

compiler/backend/src/org/jetbrains/jet/codegen/StackValue.java

@@ -230,9 +230,12 @@ public abstract class StackValue {
             pop(fromType, v);
         }
         else if (fromType.getSort() == Type.VOID) {
-            if (toType.getSort() == Type.OBJECT) {
+            if (toType.equals(JET_UNIT_TYPE) || toType.equals(OBJECT_TYPE)) {
                 putUnitInstance(v);
             }
+            else if (toType.getSort() == Type.OBJECT || toType.getSort() == Type.ARRAY) {
+                v.aconst(null);
+            }
             else {
                 pushDefaultPrimitiveValueOnStack(toType, v);
             }

compiler/testData/codegen/box/functions/coerceVoidToArray.kt

@@ -0,0 +1,16 @@
+fun a(): IntArray? = null
+
+fun b() = throw Exception()
+
+fun foo(): IntArray = a() ?: b()
+
+
+fun box(): String {
+    try {
+        foo()
+    } catch (e: Exception) {
+        return "OK"
+    }
+
+    return "Fail"
+}

compiler/testData/codegen/box/functions/coerceVoidToObject.kt

@@ -0,0 +1,16 @@
+fun a(): String? = null
+
+fun b() = throw Exception()
+
+fun foo(): String = a() ?: b()
+
+
+fun box(): String {
+    try {
+        foo()
+    } catch (e: Exception) {
+        return "OK"
+    }
+
+    return "Fail"
+}

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

@@ -1897,6 +1897,16 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), "org.jetbrains.jet.generators.tests.GenerateTests", new File("compiler/testData/codegen/box/functions"), Pattern.compile("^(.+)\\.kt$"), true);
         }
         
+        @TestMetadata("coerceVoidToArray.kt")
+        public void testCoerceVoidToArray() throws Exception {
+            doTest("compiler/testData/codegen/box/functions/coerceVoidToArray.kt");
+        }
+        
+        @TestMetadata("coerceVoidToObject.kt")
+        public void testCoerceVoidToObject() throws Exception {
+            doTest("compiler/testData/codegen/box/functions/coerceVoidToObject.kt");
+        }
+        
         @TestMetadata("defaultargs.kt")
         public void testDefaultargs() throws Exception {
             doTest("compiler/testData/codegen/box/functions/defaultargs.kt");