double-check mutability inside Allocation

RalfJung · RalfJung · commit 719dafc48b3a · 2021-06-28T09:19:36.000+02:00
diff --git a/compiler/rustc_middle/src/mir/interpret/allocation.rs b/compiler/rustc_middle/src/mir/interpret/allocation.rs
@@ -340,6 +340,8 @@ impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
         range: AllocRange,
         val: ScalarMaybeUninit<Tag>,
     ) -> AllocResult {
+        assert!(self.mutability == Mutability::Mut);
+
         let val = match val {
             ScalarMaybeUninit::Scalar(scalar) => scalar,
             ScalarMaybeUninit::Uninit => {
@@ -463,6 +465,7 @@ impl<Tag: Copy, Extra> Allocation<Tag, Extra> {
         if range.size.bytes() == 0 {
             return;
         }
+        assert!(self.mutability == Mutability::Mut);
         self.init_mask.set_range(range.start, range.end(), is_init);
     }
 }

Original file line number	Diff line number	Diff line change
`@@ -340,6 +340,8 @@ impl<Tag: Copy, Extra> Allocation<Tag, Extra> {`
`340`	`340`	`range: AllocRange,`
`341`	`341`	`val: ScalarMaybeUninit<Tag>,`
`342`	`342`	`) -> AllocResult {`
	`343`	`+ assert!(self.mutability == Mutability::Mut);`
	`344`	`+`
`343`	`345`	`let val = match val {`
`344`	`346`	`ScalarMaybeUninit::Scalar(scalar) => scalar,`
`345`	`347`	`ScalarMaybeUninit::Uninit => {`
`@@ -463,6 +465,7 @@ impl<Tag: Copy, Extra> Allocation<Tag, Extra> {`
`463`	`465`	`if range.size.bytes() == 0 {`
`464`	`466`	`return;`
`465`	`467`	`}`
	`468`	`+ assert!(self.mutability == Mutability::Mut);`
`466`	`469`	`self.init_mask.set_range(range.start, range.end(), is_init);`
`467`	`470`	`}`
`468`	`471`	`}`