closure type inference bug

[philberty]

I tried this code: https://godbolt.org/z/aKPfG1Khf

#[lang = "sized"]
pub trait Sized {}

#[lang = "fn_once"]
pub trait FnOnce<Args> {
    #[lang = "fn_once_output"]
    type Output;

    extern "rust-call" fn call_once(self, args: Args) -> Self::Output;
}

pub fn test() {
    let add: fn(&i32, &i32) -> i32 = |x, y| {
    	*x + *y
    };
}

I expected to see this happen: compile without error

Instead, this happened:

x86-64 GCCRS (GCCRS master) - 579ms

<source>:15:16: error: expected reference type got T?
   15 |         *x + *y
      |                ^
<source>:15:21: error: expected reference type got T?
   15 |         *x + *y
      |                     ^
<source>:15:16: error: cannot apply this operator to types <tyty::error> and <tyty::error>
   15 |         *x + *y
      |                ^
<source>:14:5: error: bounds not satisfied for fnptr (& i32 ,& i32 ,) -> i32 'FnOnce' is not satisfied [E0277]
   14 |     let add: fn(&i32, &i32) -> i32 = |x, y| {
      |     ^~~    

Meta

• What version of Rust GCC were you using, git sha if possible.

[philberty]

I think this is one of those cases that additions or any binop is meant to return with a new inference variable with the constraints that rhey can be derefed