rustc: don't ICE when using Rvalue::Discriminant on a non-ADT.

eddyb · Mark-Simulacrum · commit 6369d43efb46 · 2018-02-11T10:57:07.000-07:00
diff --git a/src/librustc/mir/tcx.rs b/src/librustc/mir/tcx.rs
@@ -182,9 +182,8 @@ impl<'tcx> Rvalue<'tcx> {
                 if let ty::TyAdt(adt_def, _) = ty.sty {
                     adt_def.repr.discr_type().to_ty(tcx)
                 } else {
-                    // Undefined behaviour, bug for now; may want to return something for
-                    // the `discriminant` intrinsic later.
-                    bug!("Rvalue::Discriminant on Place of type {:?}", ty);
+                    // This can only be `0`, for now, so `u8` will suffice.
+                    tcx.types.u8
                 }
             }
             Rvalue::NullaryOp(NullOp::Box, t) => tcx.mk_box(t),

Original file line number	Diff line number	Diff line change
`@@ -182,9 +182,8 @@ impl<'tcx> Rvalue<'tcx> {`
`182`	`182`	`if let ty::TyAdt(adt_def, _) = ty.sty {`
`183`	`183`	`adt_def.repr.discr_type().to_ty(tcx)`
`184`	`184`	`} else {`
`185`		`- // Undefined behaviour, bug for now; may want to return something for`
`186`		- // the `discriminant` intrinsic later.
`187`		`- bug!("Rvalue::Discriminant on Place of type {:?}", ty);`
	`185`	+ // This can only be `0`, for now, so `u8` will suffice.
	`186`	`+ tcx.types.u8`
`188`	`187`	`}`
`189`	`188`	`}`
`190`	`189`	`Rvalue::NullaryOp(NullOp::Box, t) => tcx.mk_box(t),`