Rollup merge of rust-lang#120270 - compiler-errors:randos, r=lcnr

A bunch of random modifications

r? oli-obk

Kitchen sink of changes that I didn't know where to put elsewhere. Documentation tweaks mostly, but also removing some unreachable code and simplifying the pretty printing for closures/coroutines.

Author: fmease

compiler/rustc_hir_analysis/src/autoderef.rs

@@ -12,7 +12,9 @@ use rustc_trait_selection::traits::StructurallyNormalizeExt;
 
 #[derive(Copy, Clone, Debug)]
 pub enum AutoderefKind {
+    /// A true pointer type, such as `&T` and `*mut T`.
     Builtin,
+    /// A type which must dispatch to a `Deref` implementation.
     Overloaded,
 }
 
@@ -83,6 +85,7 @@ impl<'a, 'tcx> Iterator for Autoderef<'a, 'tcx> {
                 (AutoderefKind::Builtin, ty)
             }
         } else if let Some(ty) = self.overloaded_deref_ty(self.state.cur_ty) {
+            // The overloaded deref check already normalizes the pointee type.
             (AutoderefKind::Overloaded, ty)
         } else {
             return None;

compiler/rustc_hir_analysis/src/check/compare_impl_item.rs

@@ -254,7 +254,7 @@ fn compare_method_predicate_entailment<'tcx>(
     // checks. For the comparison to be valid, we need to
     // normalize the associated types in the impl/trait methods
     // first. However, because function types bind regions, just
-    // calling `normalize_associated_types_in` would have no effect on
+    // calling `FnCtxt::normalize` would have no effect on
     // any associated types appearing in the fn arguments or return
     // type.
 

compiler/rustc_hir_typeck/src/method/probe.rs

@@ -746,11 +746,13 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
             let (xform_self_ty, xform_ret_ty) = self.xform_self_ty(item, impl_ty, impl_args);
             debug!("xform_self_ty: {:?}, xform_ret_ty: {:?}", xform_self_ty, xform_ret_ty);
 
-            // We can't use normalize_associated_types_in as it will pollute the
+            // We can't use `FnCtxt::normalize` as it will pollute the
             // fcx's fulfillment context after this probe is over.
+            //
             // Note: we only normalize `xform_self_ty` here since the normalization
             // of the return type can lead to inference results that prohibit
             // valid candidates from being found, see issue #85671
+            //
             // FIXME Postponing the normalization of the return type likely only hides a deeper bug,
             // which might be caused by the `param_env` itself. The clauses of the `param_env`
             // maybe shouldn't include `Param`s, but rather fresh variables or be canonicalized,

compiler/rustc_middle/src/ty/print/pretty.rs

@@ -804,17 +804,12 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
                     }
                 } else {
                     p!(print_def_path(did, args));
-                    p!(" upvar_tys=(");
-                    if !args.as_coroutine().is_valid() {
-                        p!("unavailable");
-                    } else {
-                        self.comma_sep(args.as_coroutine().upvar_tys().iter())?;
-                    }
-                    p!(")");
-
-                    if args.as_coroutine().is_valid() {
-                        p!(" ", print(args.as_coroutine().witness()));
-                    }
+                    p!(
+                        " upvar_tys=",
+                        print(args.as_coroutine().tupled_upvars_ty()),
+                        " witness=",
+                        print(args.as_coroutine().witness())
+                    );
                 }
 
                 p!("}}")
@@ -868,19 +863,14 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
                     }
                 } else {
                     p!(print_def_path(did, args));
-                    if !args.as_closure().is_valid() {
-                        p!(" closure_args=(unavailable)");
-                        p!(write(" args={}", args.print_as_list()));
-                    } else {
-                        p!(" closure_kind_ty=", print(args.as_closure().kind_ty()));
-                        p!(
-                            " closure_sig_as_fn_ptr_ty=",
-                            print(args.as_closure().sig_as_fn_ptr_ty())
-                        );
-                        p!(" upvar_tys=(");
-                        self.comma_sep(args.as_closure().upvar_tys().iter())?;
-                        p!(")");
-                    }
+                    p!(
+                        " closure_kind_ty=",
+                        print(args.as_closure().kind_ty()),
+                        " closure_sig_as_fn_ptr_ty=",
+                        print(args.as_closure().sig_as_fn_ptr_ty()),
+                        " upvar_tys=",
+                        print(args.as_closure().tupled_upvars_ty())
+                    );
                 }
                 p!("}}");
             }

compiler/rustc_middle/src/ty/sty.rs

@@ -242,9 +242,15 @@ pub struct ClosureArgs<'tcx> {
 
 /// Struct returned by `split()`.
 pub struct ClosureArgsParts<'tcx> {
+    /// This is the args of the typeck root.
     pub parent_args: &'tcx [GenericArg<'tcx>],
+    /// Represents the maximum calling capability of the closure.
     pub closure_kind_ty: Ty<'tcx>,
+    /// Captures the closure's signature. This closure signature is "tupled", and
+    /// thus has a peculiar signature of `extern "rust-call" fn((Args, ...)) -> Ty`.
     pub closure_sig_as_fn_ptr_ty: Ty<'tcx>,
+    /// The upvars captured by the closure. Remains an inference variable
+    /// until the upvar analysis, which happens late in HIR typeck.
     pub tupled_upvars_ty: Ty<'tcx>,
 }
 
@@ -277,15 +283,6 @@ impl<'tcx> ClosureArgs<'tcx> {
         }
     }
 
-    /// Returns `true` only if enough of the synthetic types are known to
-    /// allow using all of the methods on `ClosureArgs` without panicking.
-    ///
-    /// Used primarily by `ty::print::pretty` to be able to handle closure
-    /// types that haven't had their synthetic types substituted in.
-    pub fn is_valid(self) -> bool {
-        self.args.len() >= 3 && matches!(self.split().tupled_upvars_ty.kind(), Tuple(_))
-    }
-
     /// Returns the substitutions of the closure's parent.
     pub fn parent_args(self) -> &'tcx [GenericArg<'tcx>] {
         self.split().parent_args
@@ -296,9 +293,9 @@ impl<'tcx> ClosureArgs<'tcx> {
     /// empty iterator is returned.
     #[inline]
     pub fn upvar_tys(self) -> &'tcx List<Ty<'tcx>> {
-        match self.tupled_upvars_ty().kind() {
+        match *self.tupled_upvars_ty().kind() {
             TyKind::Error(_) => ty::List::empty(),
-            TyKind::Tuple(..) => self.tupled_upvars_ty().tuple_fields(),
+            TyKind::Tuple(tys) => tys,
             TyKind::Infer(_) => bug!("upvar_tys called before capture types are inferred"),
             ty => bug!("Unexpected representation of upvar types tuple {:?}", ty),
         }
@@ -337,10 +334,9 @@ impl<'tcx> ClosureArgs<'tcx> {
 
     /// Extracts the signature from the closure.
     pub fn sig(self) -> ty::PolyFnSig<'tcx> {
-        let ty = self.sig_as_fn_ptr_ty();
-        match ty.kind() {
-            ty::FnPtr(sig) => *sig,
-            _ => bug!("closure_sig_as_fn_ptr_ty is not a fn-ptr: {:?}", ty.kind()),
+        match *self.sig_as_fn_ptr_ty().kind() {
+            ty::FnPtr(sig) => sig,
+            ty => bug!("closure_sig_as_fn_ptr_ty is not a fn-ptr: {ty:?}"),
         }
     }
 
@@ -356,11 +352,17 @@ pub struct CoroutineArgs<'tcx> {
 }
 
 pub struct CoroutineArgsParts<'tcx> {
+    /// This is the args of the typeck root.
     pub parent_args: &'tcx [GenericArg<'tcx>],
     pub resume_ty: Ty<'tcx>,
     pub yield_ty: Ty<'tcx>,
     pub return_ty: Ty<'tcx>,
+    /// The interior type of the coroutine.
+    /// Represents all types that are stored in locals
+    /// in the coroutine's body.
     pub witness: Ty<'tcx>,
+    /// The upvars captured by the closure. Remains an inference variable
+    /// until the upvar analysis, which happens late in HIR typeck.
     pub tupled_upvars_ty: Ty<'tcx>,
 }
 
@@ -397,15 +399,6 @@ impl<'tcx> CoroutineArgs<'tcx> {
         }
     }
 
-    /// Returns `true` only if enough of the synthetic types are known to
-    /// allow using all of the methods on `CoroutineArgs` without panicking.
-    ///
-    /// Used primarily by `ty::print::pretty` to be able to handle coroutine
-    /// types that haven't had their synthetic types substituted in.
-    pub fn is_valid(self) -> bool {
-        self.args.len() >= 5 && matches!(self.split().tupled_upvars_ty.kind(), Tuple(_))
-    }
-
     /// Returns the substitutions of the coroutine's parent.
     pub fn parent_args(self) -> &'tcx [GenericArg<'tcx>] {
         self.split().parent_args
@@ -425,9 +418,9 @@ impl<'tcx> CoroutineArgs<'tcx> {
     /// empty iterator is returned.
     #[inline]
     pub fn upvar_tys(self) -> &'tcx List<Ty<'tcx>> {
-        match self.tupled_upvars_ty().kind() {
+        match *self.tupled_upvars_ty().kind() {
             TyKind::Error(_) => ty::List::empty(),
-            TyKind::Tuple(..) => self.tupled_upvars_ty().tuple_fields(),
+            TyKind::Tuple(tys) => tys,
             TyKind::Infer(_) => bug!("upvar_tys called before capture types are inferred"),
             ty => bug!("Unexpected representation of upvar types tuple {:?}", ty),
         }

compiler/rustc_trait_selection/src/solve/normalizes_to/weak_types.rs

@@ -1,7 +1,7 @@
 //! Computes a normalizes-to (projection) goal for inherent associated types,
 //! `#![feature(lazy_type_alias)]` and `#![feature(type_alias_impl_trait)]`.
 //!
-//! Since a weak alias is not ambiguous, this just computes the `type_of` of
+//! Since a weak alias is never ambiguous, this just computes the `type_of` of
 //! the alias and registers the where-clauses of the type alias.
 use rustc_middle::traits::solve::{Certainty, Goal, GoalSource, QueryResult};
 use rustc_middle::ty;

compiler/rustc_trait_selection/src/traits/query/dropck_outlives.rs

@@ -232,32 +232,12 @@ pub fn dtorck_constraint_for_ty_inner<'tcx>(
             Ok::<_, NoSolution>(())
         })?,
 
-        ty::Closure(_, args) => {
-            if !args.as_closure().is_valid() {
-                // By the time this code runs, all type variables ought to
-                // be fully resolved.
-
-                tcx.dcx().span_delayed_bug(
-                    span,
-                    format!("upvar_tys for closure not found. Expected capture information for closure {ty}",),
-                );
-                return Err(NoSolution);
+        ty::Closure(_, args) => rustc_data_structures::stack::ensure_sufficient_stack(|| {
+            for ty in args.as_closure().upvar_tys() {
+                dtorck_constraint_for_ty_inner(tcx, param_env, span, depth + 1, ty, constraints)?;
             }
-
-            rustc_data_structures::stack::ensure_sufficient_stack(|| {
-                for ty in args.as_closure().upvar_tys() {
-                    dtorck_constraint_for_ty_inner(
-                        tcx,
-                        param_env,
-                        span,
-                        depth + 1,
-                        ty,
-                        constraints,
-                    )?;
-                }
-                Ok::<_, NoSolution>(())
-            })?
-        }
+            Ok::<_, NoSolution>(())
+        })?,
 
         ty::Coroutine(_, args) => {
             // rust-lang/rust#49918: types can be constructed, stored
@@ -283,15 +263,6 @@ pub fn dtorck_constraint_for_ty_inner<'tcx>(
             // derived from lifetimes attached to the upvars and resume
             // argument, and we *do* incorporate those here.
             let args = args.as_coroutine();
-            if !args.is_valid() {
-                // By the time this code runs, all type variables ought to
-                // be fully resolved.
-                tcx.dcx().span_delayed_bug(
-                    span,
-                    format!("upvar_tys for coroutine not found. Expected capture information for coroutine {ty}",),
-                );
-                return Err(NoSolution);
-            }
 
             // While we conservatively assume that all coroutines require drop
             // to avoid query cycles during MIR building, we can check the actual

compiler/rustc_trait_selection/src/traits/query/type_op/mod.rs

@@ -141,6 +141,13 @@ where
         infcx: &InferCtxt<'tcx>,
         span: Span,
     ) -> Result<TypeOpOutput<'tcx, Self>, ErrorGuaranteed> {
+        // In the new trait solver, query type ops are performed locally. This
+        // is because query type ops currently use the old canonicalizer, and
+        // that doesn't preserve things like opaques which have been registered
+        // during MIR typeck. Even after the old canonicalizer is gone, it's
+        // probably worthwhile just keeping this run-locally logic, since we
+        // probably don't gain much from caching here given the new solver does
+        // caching internally.
         if infcx.next_trait_solver() {
             return Ok(scrape_region_constraints(
                 infcx,

tests/ui/closures/print/closure-print-generic-trim-off-verbose-2.stderr

@@ -9,7 +9,7 @@ LL |         let c1 : () = c;
    |                  expected due to this
    |
    = note: expected unit type `()`
-                found closure `{mod1::f<T>::{closure#0} closure_args=(unavailable) args=[T, ?8t, extern "rust-call" fn(()), ?7t]}`
+                found closure `{mod1::f<T>::{closure#0} closure_kind_ty=?8t closure_sig_as_fn_ptr_ty=extern "rust-call" fn(()) upvar_tys=?7t}`
 help: use parentheses to call this closure
    |
 LL |         let c1 : () = c();

tests/ui/closures/print/closure-print-generic-verbose-2.stderr

@@ -9,7 +9,7 @@ LL |         let c1 : () = c;
    |                  expected due to this
    |
    = note: expected unit type `()`
-                found closure `{f<T>::{closure#0} closure_args=(unavailable) args=[T, ?8t, extern "rust-call" fn(()), ?7t]}`
+                found closure `{f<T>::{closure#0} closure_kind_ty=?8t closure_sig_as_fn_ptr_ty=extern "rust-call" fn(()) upvar_tys=?7t}`
 help: use parentheses to call this closure
    |
 LL |         let c1 : () = c();