Type level consts can show up in MIR type checker

Author: compiler-errors

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -349,8 +349,8 @@ impl<'a, 'b, 'tcx> Visitor<'tcx> for TypeVerifier<'a, 'b, 'tcx> {
             let tcx = self.tcx();
             let maybe_uneval = match constant.const_ {
                 Const::Ty(_, ct) => match ct.kind() {
-                    ty::ConstKind::Unevaluated(_) => {
-                        bug!("should not encounter unevaluated Const::Ty here, got {:?}", ct)
+                    ty::ConstKind::Unevaluated(uv) => {
+                        Some(UnevaluatedConst { def: uv.def, args: uv.args, promoted: None })
                     }
                     _ => None,
                 },

compiler/rustc_mir_build/src/builder/expr/as_place.rs

@@ -651,8 +651,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 // though. FIXME: Do we really *need* to count this as a use?
                 // Could partial array tracking work off something else instead?
                 self.cfg.push_fake_read(block, source_info, FakeReadCause::ForIndex, place);
-                let const_ = Const::from_ty_const(*len_const, self.tcx.types.usize, self.tcx);
-                Operand::Constant(Box::new(ConstOperand { span, user_ty: None, const_ }))
+                Operand::Constant(Box::new(ConstOperand {
+                    span,
+                    user_ty: None,
+                    const_: Const::Ty(self.tcx.types.usize, *len_const),
+                }))
             }
             ty::Slice(_elem_ty) => {
                 let ptr_or_ref = if let [PlaceElem::Deref] = place.projection[..]

tests/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.GVN.32bit.panic-abort.diff

@@ -30,8 +30,7 @@
           StorageDead(_2);
           StorageDead(_3);
           StorageLive(_5);
--         StorageLive(_6);
-+         nop;
+          StorageLive(_6);
           _6 = const 3_usize;
 -         _7 = PtrMetadata(copy _1);
 -         _8 = Lt(copy _6, copy _7);
@@ -43,9 +42,8 @@
 
       bb1: {
 -         _5 = copy (*_1)[_6];
--         StorageDead(_6);
 +         _5 = copy (*_1)[3 of 4];
-+         nop;
+          StorageDead(_6);
           _0 = const ();
           StorageDead(_5);
           StorageDead(_1);

tests/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.GVN.32bit.panic-unwind.diff

@@ -30,8 +30,7 @@
           StorageDead(_2);
           StorageDead(_3);
           StorageLive(_5);
--         StorageLive(_6);
-+         nop;
+          StorageLive(_6);
           _6 = const 3_usize;
 -         _7 = PtrMetadata(copy _1);
 -         _8 = Lt(copy _6, copy _7);
@@ -43,9 +42,8 @@
 
       bb1: {
 -         _5 = copy (*_1)[_6];
--         StorageDead(_6);
 +         _5 = copy (*_1)[3 of 4];
-+         nop;
+          StorageDead(_6);
           _0 = const ();
           StorageDead(_5);
           StorageDead(_1);

tests/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.GVN.64bit.panic-abort.diff

@@ -30,8 +30,7 @@
           StorageDead(_2);
           StorageDead(_3);
           StorageLive(_5);
--         StorageLive(_6);
-+         nop;
+          StorageLive(_6);
           _6 = const 3_usize;
 -         _7 = PtrMetadata(copy _1);
 -         _8 = Lt(copy _6, copy _7);
@@ -43,9 +42,8 @@
 
       bb1: {
 -         _5 = copy (*_1)[_6];
--         StorageDead(_6);
 +         _5 = copy (*_1)[3 of 4];
-+         nop;
+          StorageDead(_6);
           _0 = const ();
           StorageDead(_5);
           StorageDead(_1);

tests/mir-opt/const_prop/bad_op_unsafe_oob_for_slices.main.GVN.64bit.panic-unwind.diff

@@ -30,8 +30,7 @@
           StorageDead(_2);
           StorageDead(_3);
           StorageLive(_5);
--         StorageLive(_6);
-+         nop;
+          StorageLive(_6);
           _6 = const 3_usize;
 -         _7 = PtrMetadata(copy _1);
 -         _8 = Lt(copy _6, copy _7);
@@ -43,9 +42,8 @@
 
       bb1: {
 -         _5 = copy (*_1)[_6];
--         StorageDead(_6);
 +         _5 = copy (*_1)[3 of 4];
-+         nop;
+          StorageDead(_6);
           _0 = const ();
           StorageDead(_5);
           StorageDead(_1);

tests/mir-opt/nll/region_subtyping_basic.main.nll.0.32bit.mir

@@ -52,8 +52,8 @@ fn main() -> () {
         StorageLive(_3);
         _3 = const ConstValue(Scalar(0x00000000): usize);
         FakeRead(ForIndex, _1);
-        _4 = Lt(copy _3, const ConstValue(Scalar(0x00000003): usize));
-        assert(move _4, "index out of bounds: the length is {} but the index is {}", const ConstValue(Scalar(0x00000003): usize), copy _3) -> [success: bb1, unwind: bb7];
+        _4 = Lt(copy _3, const ValTree(Leaf(0x00000003): usize));
+        assert(move _4, "index out of bounds: the length is {} but the index is {}", const ValTree(Leaf(0x00000003): usize), copy _3) -> [success: bb1, unwind: bb7];
     }
 
     bb1: {

tests/mir-opt/nll/region_subtyping_basic.main.nll.0.64bit.mir

@@ -52,8 +52,8 @@ fn main() -> () {
         StorageLive(_3);
         _3 = const ConstValue(Scalar(0x0000000000000000): usize);
         FakeRead(ForIndex, _1);
-        _4 = Lt(copy _3, const ConstValue(Scalar(0x0000000000000003): usize));
-        assert(move _4, "index out of bounds: the length is {} but the index is {}", const ConstValue(Scalar(0x0000000000000003): usize), copy _3) -> [success: bb1, unwind: bb7];
+        _4 = Lt(copy _3, const ValTree(Leaf(0x0000000000000003): usize));
+        assert(move _4, "index out of bounds: the length is {} but the index is {}", const ValTree(Leaf(0x0000000000000003): usize), copy _3) -> [success: bb1, unwind: bb7];
     }
 
     bb1: {