Change:
The compiler correctly warns that the second fail is unreachable, then an ICE occurs
rusttaskfail (task=0x10250a1f0, expr=0x100ca7fc0 "Assertion llvm::LLVMGetPointerAddressSpace(valty(val)) == gcboxaddrspace failed", file=0x100ca7ed0 "", line=270) at /Users/jdm/sr 0x0000000100ffff8b in morestack () at rustshape.h:493 0x0000000100fe98af in rusttask::returncstack () at /Users/jdm/src/rust/src/rt/rusttask.h:476 0x0000000100fe98af in upcallfail (expr=<value temporarily unavailable, due to optimizations, file=0x100ca7ed0 "", line=270) at rusttask.h:481 0x0000000100811768 in middle::trans::base::nongcboxcast::::05 () 0x00000001007d8ed0 in middle::trans::tvec::transuniqormanagedvstore::::05 () 0x00000001007d392c in middle::trans::expr::transrvaluedatumunadjusted::::05 () 0x00000001007d1602 in middle::trans::expr::transtodatumunadjusted::::05 () 0x000000010078d0d4 in middle::trans::expr::transtodatum::::05 () 0x0000000100ca2180 in morestack () 0x000000010079badb in middle::trans::controlflow::transfailexpr::::_05 ()
Fixed by jdm

Discussion:
## [Unreleased] <ins> ## [1.4.9] 2019-10-07 ### Changed - Update `rustc-ap-*` crates to 606.0.0. ### Fixed - Fix aligning comments of different group - Fix flattening imports with a single `self`. - Fix removing attributes on function parameters. - Fix removing `impl` keyword from opaque type. </ins> ## [1.4.8] 2019-09-08 ### Changed

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