Avoid extra arity and type check on distinguishing argument

Source/bindings/tests/idls/TestObject.idl

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@@ skipping 392 matching lines @@
     // FIXME: Should be in order double, Dictionary, but Blink implementation of
     // overload resolution can't handle this. http://crbug.com/293561
     void overloadedMethodI(Dictionary dictionaryArg); // Non-wrapper type
     void overloadedMethodI(double doubleArg);
     void overloadedMethodJ(long longArg);
     void overloadedMethodJ([Default=Null] TestInterfaceEmpty? testInterfaceEmptyOrNullArg);
     void overloadedMethodK(TestInterface testInterfaceArg);
     void overloadedMethodK(TestInterfaceEmpty testInterfaceEmptyArg);
     void overloadedMethodL(DOMString stringArg);
     void overloadedMethodL(double doubleArg);
+    [TypeChecking=Interface] void overloadedMethodM(TestInterface testInterfaceArg1, TestInterface testInterfaceArg2);
+    [TypeChecking=Interface] void overloadedMethodM(TestInterface testInterfaceArg, TestInterfaceEmpty testInterfaceEmptyArg);
+    [TypeChecking=Interface] void overloadedMethodN(double a, TestInterface b);

[Nils Barth (inactive), 2014/05/16 02:15:46]

You don't need the double here do you?
...and this is subtle enough that some comment on what's being tested would be
good:
// 2 distinguishing argument indices in second method, due to optionality

[Jens Widell, 2014/05/16 05:59:17]

Don't think I do, no. Unclear why I thought I did.
Yeah. By the time I added this, I had sort of already abandoned this CL in my
mind anyway, so wasn't being too thorough here.

Do you think it meaningful to add these methods on their own?

[Nils Barth (inactive), 2014/05/16 06:05:31]

I don't think that's necessary, but thanks for asking!
Generally we only add test cases when there's an actual use case that fails
otherwise, not just for internal correctness tests.

(We try to keep CG and test cases close to actual usage: that's why I've been
avoiding adding correct CG code that's unused: dead code rots quickly around
here.)

+    [TypeChecking=Interface] void overloadedMethodN(double a, TestInterfaceEmpty b, optional TestInterface c);
+    [TypeChecking=Interface] void overloadedMethodN(double a, TestInterfaceEmpty b, TestInterfaceEmpty c);
 
 
     [PerWorldBindings] void overloadedPerWorldBindingsMethod();
     [PerWorldBindings] void overloadedPerWorldBindingsMethod(long longArg);
 
     static void overloadedStaticMethod(long longArg);
     static void overloadedStaticMethod(long longArg1, long longArg2);
 
     // Extended attributes for arguments
     // [Clamp]
@@ skipping 75 matching lines @@
     void voidMethodTestInterfaceWillBeGarbageCollectedArrayArg(TestInterfaceWillBeGarbageCollected[] testInterfaceWillBeGarbageCollectedArrayArg);
 
     // Extended attributes on referenced interfaces
     // (not self; self-reference tests at interface themselves)
     attribute TestInterface testInterfaceAttribute; // [ImplementedAs]
     attribute TestInterfaceGarbageCollected testInterfaceGarbageCollectedAttribute; // [GarbageCollected]
     attribute TestInterfaceGarbageCollected? testInterfaceGarbageCollectedOrNullAttribute; // [GarbageCollected]
     attribute TestInterfaceWillBeGarbageCollected testInterfaceWillBeGarbageCollectedAttribute; // [WillBeGarbageCollected]
     attribute TestInterfaceWillBeGarbageCollected? testInterfaceWillBeGarbageCollectedOrNullAttribute; // [WillBeGarbageCollected]
 };