invalid cast opcode for cast from 'i1 (i16*, %"fmt::Formatter"*) addrspace(1)*' to 'i8*'

[shepmaster]

@_ZN4core3fmt12USIZE_MARKER17h5ad02df6e9f33d4eE = constant <{ i8*, [0 x i8] }> <{ i8* bitcast (i1 (i16*, %"fmt::Formatter"*) addrspace(1)* @_ZN4core3ops8function6FnOnce9call_once17h57a79d3d932cd0d6E to i8*), [0 x i8] zeroinitializer }>, align 1, !dbg !448

This sure feels like our hack to workaround pointers isn't sufficient.

[shepmaster]

Similar issue in core::fmt::run:

  %_19 = bitcast i8* %value.1 to i1 (%"fmt::::Opaque"*, %"fmt::Formatter"*) addrspace(1)*, !dbg !26226