bad substs for tuple-like constructor function pointer

[solson]

Source

fn main() {
    let f: fn(i32) -> Option<i32> = Some::<i32>;
    f(42);
}

Output and error

TRACE:miri::step:  _1 = std::option::Option<i32>::Some as fn(i32) -> std::option::Option<i32> (ReifyFnPointer)
TRACE:miri::eval_context:  _1: Undef
DEBUG:miri::memory: creating fn ptr: 2
TRACE:miri::eval_context:  _1: Ptr(Pointer { alloc_id: AllocId(2), offset: 0 })
TRACE:miri::memory:  Alloc 2:     function pointer: std::prelude::v1::Some: fn(i32) -> std::option::Option<i32>
TRACE:miri::step:  StorageLive(_3)
TRACE:miri::step:  _3 = _1
TRACE:miri::eval_context:  _3: Undef
TRACE:miri::eval_context:  _1: Ptr(Pointer { alloc_id: AllocId(2), offset: 0 })
TRACE:miri::memory:  Alloc 2:     function pointer: std::prelude::v1::Some: fn(i32) -> std::option::Option<i32>
TRACE:miri::eval_context:  _3: Ptr(Pointer { alloc_id: AllocId(2), offset: 0 })
TRACE:miri::memory:  Alloc 2:     function pointer: std::prelude::v1::Some: fn(i32) -> std::option::Option<i32>
TRACE:miri::step:  _2 = _3(const 42i32) -> bb1
TRACE:miri::eval_context:  _2: Undef
TRACE:miri::eval_context:  _3: Ptr(Pointer { alloc_id: AllocId(2), offset: 0 })
TRACE:miri::memory:  Alloc 2:     function pointer: std::prelude::v1::Some: fn(i32) -> std::option::Option<i32>
DEBUG:miri::memory: reading fn ptr: 2
error: internal compiler error: /buildslave/rust-buildbot/slave/nightly-dist-rustc-linux/build/src/librustc/ty/subst.rs:476: Type parameter `T/#0` (T/0) out of range when substituting (root type=Some(std::option::Option<T>)) substs=[]

[solson]

I want to look into this but I won't have time for a couple days, so if someone else starts working on it, please let me know.