Auto merge of rust-lang#96046 - oli-obk:const_typeck, r=cjgillot

Move various checks to typeck so them failing causes the typeck result to get tainted

Fixes rust-lang#69487
fixes rust-lang#79047

cc `@RalfJung` this gets rid of the `Transmute` invalid program error variant

Author: bors

compiler/rustc_const_eval/src/interpret/place.rs

@@ -906,16 +906,12 @@ where
         }
         // We still require the sizes to match.
         if src.layout.size != dest.layout.size {
-            // FIXME: This should be an assert instead of an error, but if we transmute within an
-            // array length computation, `typeck` may not have yet been run and errored out. In fact
-            // most likely we *are* running `typeck` right now. Investigate whether we can bail out
-            // on `typeck_results().has_errors` at all const eval entry points.
-            debug!("Size mismatch when transmuting!\nsrc: {:#?}\ndest: {:#?}", src, dest);
-            self.tcx.sess.delay_span_bug(
+            span_bug!(
                 self.cur_span(),
-                "size-changing transmute, should have been caught by transmute checking",
+                "size-changing transmute, should have been caught by transmute checking: {:#?}\ndest: {:#?}",
+                src,
+                dest
             );
-            throw_inval!(TransmuteSizeDiff(src.layout.ty, dest.layout.ty));
         }
         // Unsized copies rely on interpreting `src.meta` with `dest.layout`, we want
         // to avoid that here.

compiler/rustc_interface/src/passes.rs

@@ -937,7 +937,6 @@ fn analysis(tcx: TyCtxt<'_>, (): ()) -> Result<()> {
                         //
                         // maybe move the check to a MIR pass?
                         tcx.ensure().check_mod_liveness(module);
-                        tcx.ensure().check_mod_intrinsics(module);
                     });
                 });
             }

compiler/rustc_middle/src/mir/interpret/error.rs

@@ -149,8 +149,6 @@ pub enum InvalidProgramInfo<'tcx> {
     /// (which unfortunately typeck does not reject).
     /// Not using `FnAbiError` as that contains a nested `LayoutError`.
     FnAbiAdjustForForeignAbi(call::AdjustForForeignAbiError),
-    /// An invalid transmute happened.
-    TransmuteSizeDiff(Ty<'tcx>, Ty<'tcx>),
     /// SizeOf of unsized type was requested.
     SizeOfUnsizedType(Ty<'tcx>),
 }
@@ -166,11 +164,6 @@ impl fmt::Display for InvalidProgramInfo<'_> {
             }
             Layout(ref err) => write!(f, "{}", err),
             FnAbiAdjustForForeignAbi(ref err) => write!(f, "{}", err),
-            TransmuteSizeDiff(from_ty, to_ty) => write!(
-                f,
-                "transmuting `{}` to `{}` is not possible, because these types do not have the same size",
-                from_ty, to_ty
-            ),
             SizeOfUnsizedType(ty) => write!(f, "size_of called on unsized type `{}`", ty),
         }
     }

compiler/rustc_middle/src/query/mod.rs

@@ -804,10 +804,6 @@ rustc_queries! {
         desc { |tcx| "checking privacy in {}", describe_as_module(key, tcx) }
     }
 
-    query check_mod_intrinsics(key: LocalDefId) -> () {
-        desc { |tcx| "checking intrinsics in {}", describe_as_module(key, tcx) }
-    }
-
     query check_mod_liveness(key: LocalDefId) -> () {
         desc { |tcx| "checking liveness of variables in {}", describe_as_module(key, tcx) }
     }

compiler/rustc_passes/src/lib.rs

@@ -30,7 +30,6 @@ mod diagnostic_items;
 pub mod entry;
 pub mod hir_id_validator;
 pub mod hir_stats;
-mod intrinsicck;
 mod lang_items;
 pub mod layout_test;
 mod lib_features;
@@ -54,7 +53,6 @@ pub fn provide(providers: &mut Providers) {
     loops::provide(providers);
     naked_functions::provide(providers);
     liveness::provide(providers);
-    intrinsicck::provide(providers);
     reachable::provide(providers);
     stability::provide(providers);
     upvars::provide(providers);

compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs

@@ -273,6 +273,7 @@ impl<'a, 'tcx> InferCtxtExt<'tcx> for InferCtxt<'a, 'tcx> {
         error: &SelectionError<'tcx>,
         fallback_has_occurred: bool,
     ) {
+        self.set_tainted_by_errors();
         let tcx = self.tcx;
         let mut span = obligation.cause.span;
 

compiler/rustc_typeck/src/check/check.rs

@@ -1,3 +1,5 @@
+use crate::check::wfcheck::for_item;
+
 use super::coercion::CoerceMany;
 use super::compare_method::check_type_bounds;
 use super::compare_method::{compare_const_impl, compare_impl_method, compare_ty_impl};
@@ -871,6 +873,14 @@ pub fn check_item_type<'tcx>(tcx: TyCtxt<'tcx>, id: hir::ItemId) {
                 }
             }
         }
+        DefKind::GlobalAsm => {
+            let it = tcx.hir().item(id);
+            let hir::ItemKind::GlobalAsm(asm) = it.kind else { span_bug!(it.span, "DefKind::GlobalAsm but got {:#?}", it) };
+            for_item(tcx, it).with_fcx(|fcx| {
+                fcx.check_asm(asm, it.hir_id());
+                Default::default()
+            })
+        }
         _ => {}
     }
 }

compiler/rustc_typeck/src/check/expr.rs

@@ -51,6 +51,7 @@ use rustc_span::lev_distance::find_best_match_for_name;
 use rustc_span::source_map::Span;
 use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{BytePos, Pos};
+use rustc_target::spec::abi::Abi::RustIntrinsic;
 use rustc_trait_selection::infer::InferCtxtExt;
 use rustc_trait_selection::traits::{self, ObligationCauseCode};
 
@@ -294,7 +295,11 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 self.check_lang_item_path(lang_item, expr, hir_id)
             }
             ExprKind::Path(ref qpath) => self.check_expr_path(qpath, expr, &[]),
-            ExprKind::InlineAsm(asm) => self.check_expr_asm(asm),
+            ExprKind::InlineAsm(asm) => {
+                // We defer some asm checks as we may not have resolved the input and output types yet (they may still be infer vars).
+                self.deferred_asm_checks.borrow_mut().push((asm, expr.hir_id));
+                self.check_expr_asm(asm)
+            }
             ExprKind::Break(destination, ref expr_opt) => {
                 self.check_expr_break(destination, expr_opt.as_deref(), expr)
             }
@@ -530,8 +535,17 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             _ => self.instantiate_value_path(segs, opt_ty, res, expr.span, expr.hir_id).0,
         };
 
-        if let ty::FnDef(..) = ty.kind() {
+        if let ty::FnDef(did, ..) = *ty.kind() {
             let fn_sig = ty.fn_sig(tcx);
+            if tcx.fn_sig(did).abi() == RustIntrinsic && tcx.item_name(did) == sym::transmute {
+                let from = fn_sig.inputs().skip_binder()[0];
+                let to = fn_sig.output().skip_binder();
+                // We defer the transmute to the end of typeck, once all inference vars have
+                // been resolved or we errored. This is important as we can only check transmute
+                // on concrete types, but the output type may not be known yet (it would only
+                // be known if explicitly specified via turbofish).
+                self.deferred_transmute_checks.borrow_mut().push((from, to, expr.span));
+            }
             if !tcx.features().unsized_fn_params {
                 // We want to remove some Sized bounds from std functions,
                 // but don't want to expose the removal to stable Rust.

compiler/rustc_typeck/src/check/fn_ctxt/checks.rs

@@ -47,6 +47,23 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         }
     }
 
+    pub(in super::super) fn check_transmutes(&self) {
+        let mut deferred_transmute_checks = self.deferred_transmute_checks.borrow_mut();
+        debug!("FnCtxt::check_transmutes: {} deferred checks", deferred_transmute_checks.len());
+        for (from, to, span) in deferred_transmute_checks.drain(..) {
+            self.check_transmute(span, from, to);
+        }
+    }
+
+    pub(in super::super) fn check_asms(&self) {
+        let mut deferred_asm_checks = self.deferred_asm_checks.borrow_mut();
+        debug!("FnCtxt::check_asm: {} deferred checks", deferred_asm_checks.len());
+        for (asm, hir_id) in deferred_asm_checks.drain(..) {
+            let enclosing_id = self.tcx.hir().enclosing_body_owner(hir_id);
+            self.check_asm(asm, enclosing_id);
+        }
+    }
+
     pub(in super::super) fn check_method_argument_types(
         &self,
         sp: Span,

compiler/rustc_typeck/src/check/inherited.rs

@@ -50,6 +50,10 @@ pub struct Inherited<'a, 'tcx> {
 
     pub(super) deferred_cast_checks: RefCell<Vec<super::cast::CastCheck<'tcx>>>,
 
+    pub(super) deferred_transmute_checks: RefCell<Vec<(Ty<'tcx>, Ty<'tcx>, Span)>>,
+
+    pub(super) deferred_asm_checks: RefCell<Vec<(&'tcx hir::InlineAsm<'tcx>, hir::HirId)>>,
+
     pub(super) deferred_generator_interiors:
         RefCell<Vec<(hir::BodyId, Ty<'tcx>, hir::GeneratorKind)>>,
 
@@ -113,6 +117,8 @@ impl<'a, 'tcx> Inherited<'a, 'tcx> {
             deferred_sized_obligations: RefCell::new(Vec::new()),
             deferred_call_resolutions: RefCell::new(Default::default()),
             deferred_cast_checks: RefCell::new(Vec::new()),
+            deferred_transmute_checks: RefCell::new(Vec::new()),
+            deferred_asm_checks: RefCell::new(Vec::new()),
             deferred_generator_interiors: RefCell::new(Vec::new()),
             diverging_type_vars: RefCell::new(Default::default()),
             body_id,