Borrowing a mutable explicit self pointer as immutable trips an LLVM assert

[pcwalton]

Test case:

struct Foo {
    x: int;
}

impl Foo {
    fn f(&self) {}
}

fn g(x: &mut Foo) {
    x.f();
}

fn main() {
}

Error:

rustc: /home/pcwalton/Source/rust/src/llvm/lib/VMCore/Instructions.cpp:1062: void llvm::StoreInst::AssertOK(): Assertion `getOperand(0)->getType() == cast<PointerType>(getOperand(1)->getType())->getElementType() && "Ptr must be a pointer to Val type!"' failed.

@nikomatsakis, any ideas?

[pcwalton]

The problem is in adapt_borrowed_value. I think I may have a hunch as to what's wrong.