bug! more uses of these in runtime stuff

Author: scottmcm

compiler/rustc_codegen_cranelift/src/base.rs

@@ -677,21 +677,22 @@ fn codegen_stmt<'tcx>(
                     CastKind::PointerCoercion(PointerCoercion::UnsafeFnPointer),
                     ref operand,
                     to_ty,
-                )
-                | Rvalue::Cast(
-                    CastKind::PointerCoercion(PointerCoercion::MutToConstPointer),
-                    ref operand,
-                    to_ty,
-                )
-                | Rvalue::Cast(
-                    CastKind::PointerCoercion(PointerCoercion::ArrayToPointer),
-                    ref operand,
-                    to_ty,
                 ) => {
                     let to_layout = fx.layout_of(fx.monomorphize(to_ty));
                     let operand = codegen_operand(fx, operand);
                     lval.write_cvalue(fx, operand.cast_pointer_to(to_layout));
                 }
+                Rvalue::Cast(
+                    CastKind::PointerCoercion(
+                        PointerCoercion::MutToConstPointer | PointerCoercion::ArrayToPointer,
+                    ),
+                    ..,
+                ) => {
+                    bug!(
+                        "{:?} is for borrowck, and should never appear in codegen",
+                        to_place_and_rval.1
+                    );
+                }
                 Rvalue::Cast(
                     CastKind::IntToInt
                     | CastKind::FloatToFloat

compiler/rustc_codegen_ssa/src/mir/rvalue.rs

@@ -456,8 +456,12 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                             base::unsize_ptr(bx, lldata, operand.layout.ty, cast.ty, llextra);
                         OperandValue::Pair(lldata, llextra)
                     }
-                    mir::CastKind::PointerCoercion(PointerCoercion::MutToConstPointer)
-                    | mir::CastKind::PtrToPtr
+                    mir::CastKind::PointerCoercion(
+                        PointerCoercion::MutToConstPointer | PointerCoercion::ArrayToPointer,
+                    ) => {
+                        bug!("{kind:?} is for borrowck, and should never appear in codegen");
+                    }
+                    mir::CastKind::PtrToPtr
                         if bx.cx().is_backend_scalar_pair(operand.layout) =>
                     {
                         if let OperandValue::Pair(data_ptr, meta) = operand.val {
@@ -477,9 +481,6 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                             base::cast_to_dyn_star(bx, lldata, operand.layout, cast.ty, llextra);
                         OperandValue::Pair(lldata, llextra)
                     }
-                    mir::CastKind::PointerCoercion(
-                        PointerCoercion::MutToConstPointer | PointerCoercion::ArrayToPointer,
-                    )
                     | mir::CastKind::IntToInt
                     | mir::CastKind::FloatToInt
                     | mir::CastKind::FloatToFloat

compiler/rustc_const_eval/src/interpret/cast.rs

@@ -70,9 +70,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
             CastKind::PointerCoercion(
                 PointerCoercion::MutToConstPointer | PointerCoercion::ArrayToPointer,
             ) => {
-                // These are NOPs, but can be wide pointers.
-                let v = self.read_immediate(src)?;
-                self.write_immediate(*v, dest)?;
+                bug!("{cast_kind:?} casts are for borrowck only, not runtime MIR");
             }
 
             CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer) => {