misc coercion cleanups and handle safety correctly

compiler/rustc_borrowck/src/type_check/mod.rs

@@ -1062,7 +1062,10 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
 
  Rvalue::Cast(cast_kind, op, ty) => {
  match *cast_kind {
- CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer, coercion_source) => {
+ CastKind::PointerCoercion(
+ PointerCoercion::ReifyFnPointer(target_safety),
+ coercion_source,
+ ) => {
  let is_implicit_coercion = coercion_source == CoercionSource::Implicit;
  let src_ty = op.ty(self.body, tcx);
  let mut src_sig = src_ty.fn_sig(tcx);
@@ -1079,6 +1082,10 @@ impl<'a, 'tcx> Visitor<'tcx> for TypeChecker<'a, 'tcx> {
  src_sig = safe_sig;
  }
 
+ if src_sig.safety().is_safe() && target_safety.is_unsafe() {
+ src_sig = tcx.safe_to_unsafe_sig(src_sig);
+ }
+
  // HACK: This shouldn't be necessary... We can remove this when we actually
  // get binders with where clauses, then elaborate implied bounds into that
  // binder, and implement a higher-ranked subtyping algorithm that actually

compiler/rustc_codegen_cranelift/src/base.rs

@@ -665,7 +665,7 @@ fn codegen_stmt<'tcx>(fx: &mut FunctionCx<'_, '_, 'tcx>, cur_block: Block, stmt:
  lval.write_cvalue(fx, res);
  }
  Rvalue::Cast(
- CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer, _),
+ CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer(_), _),
  ref operand,
  to_ty,
  ) => {

compiler/rustc_codegen_ssa/src/mir/rvalue.rs

@@ -399,7 +399,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
  let lladdr = bx.ptrtoint(llptr, llcast_ty);
  OperandValue::Immediate(lladdr)
  }
- mir::CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer, _) => {
+ mir::CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer(_), _) => {
  match *operand.layout.ty.kind() {
  ty::FnDef(def_id, args) => {
  let instance = ty::Instance::resolve_for_fn_ptr(

compiler/rustc_const_eval/src/check_consts/check.rs

@@ -627,7 +627,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
  | PointerCoercion::ArrayToPointer
  | PointerCoercion::UnsafeFnPointer
  | PointerCoercion::ClosureFnPointer(_)
- | PointerCoercion::ReifyFnPointer,
+ | PointerCoercion::ReifyFnPointer(_),
  _,
  ),
  _,

compiler/rustc_const_eval/src/interpret/cast.rs

@@ -74,7 +74,7 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
  bug!("{cast_kind:?} casts are for borrowck only, not runtime MIR");
  }
 
- CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer, _) => {
+ CastKind::PointerCoercion(PointerCoercion::ReifyFnPointer(_), _) => {
  // All reifications must be monomorphic, bail out otherwise.
  ensure_monomorphic_enough(*self.tcx, src.layout.ty)?;