Rollup merge of #93990 - lcnr:pre-89862-cleanup, r=estebank

pre #89862 cleanup

changes used in #89862 which can be landed without the rest of this PR being finished.

r? `@estebank`

8 files changed, 88 insertions, 54 deletions

diff --git a/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs b/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
index a61100d907b..205ad044554 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/need_type_info.rs
@@ -497,16 +497,32 @@ impl<'a, 'tcx> InferCtxt<'a, 'tcx> {
         let ty_to_string = |ty: Ty<'tcx>| -> String {
             let mut s = String::new();
             let mut printer = ty::print::FmtPrinter::new(self.tcx, &mut s, Namespace::TypeNS);
-            let mut inner = self.inner.borrow_mut();
-            let ty_vars = inner.type_variables();
-            let getter = move |ty_vid| {
-                let var_origin = ty_vars.var_origin(ty_vid);
-                if let TypeVariableOriginKind::TypeParameterDefinition(name, _) = var_origin.kind {
+            let ty_getter = move |ty_vid| {
+                if let TypeVariableOriginKind::TypeParameterDefinition(name, _) =
+                    self.inner.borrow_mut().type_variables().var_origin(ty_vid).kind
+                {
+                    Some(name.to_string())
+                } else {
+                    None
+                }
+            };
+            printer.ty_infer_name_resolver = Some(Box::new(ty_getter));
+            let const_getter = move |ct_vid| {
+                if let ConstVariableOriginKind::ConstParameterDefinition(name, _) = self
+                    .inner
+                    .borrow_mut()
+                    .const_unification_table()
+                    .probe_value(ct_vid)
+                    .origin
+                    .kind
+                {
                     return Some(name.to_string());
+                } else {
+                    None
                 }
-                None
             };
-            printer.name_resolver = Some(Box::new(&getter));
+            printer.const_infer_name_resolver = Some(Box::new(const_getter));
+
             let _ = if let ty::FnDef(..) = ty.kind() {
                 // We don't want the regular output for `fn`s because it includes its path in
                 // invalid pseudo-syntax, we want the `fn`-pointer output instead.
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index ae838a46157..bf7370c9e0e 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -606,7 +606,7 @@ pub trait PrettyPrinter<'tcx>:
             ty::Infer(infer_ty) => {
                 let verbose = self.tcx().sess.verbose();
                 if let ty::TyVar(ty_vid) = infer_ty {
-                    if let Some(name) = self.infer_ty_name(ty_vid) {
+                    if let Some(name) = self.ty_infer_name(ty_vid) {
                         p!(write("{}", name))
                     } else {
                         if verbose {
@@ -1015,7 +1015,11 @@ pub trait PrettyPrinter<'tcx>:
         }
     }
 
-    fn infer_ty_name(&self, _: ty::TyVid) -> Option<String> {
+    fn ty_infer_name(&self, _: ty::TyVid) -> Option<String> {
+        None
+    }
+
+    fn const_infer_name(&self, _: ty::ConstVid<'tcx>) -> Option<String> {
         None
     }
 
@@ -1203,7 +1207,14 @@ pub trait PrettyPrinter<'tcx>:
                     }
                 }
             }
-            ty::ConstKind::Infer(..) => print_underscore!(),
+            ty::ConstKind::Infer(infer_ct) => {
+                match infer_ct {
+                    ty::InferConst::Var(ct_vid)
+                        if let Some(name) = self.const_infer_name(ct_vid) =>
+                            p!(write("{}", name)),
+                    _ => print_underscore!(),
+                }
+            }
             ty::ConstKind::Param(ParamConst { name, .. }) => p!(write("{}", name)),
             ty::ConstKind::Value(value) => {
                 return self.pretty_print_const_value(value, ct.ty(), print_ty);
@@ -1559,7 +1570,8 @@ pub struct FmtPrinterData<'a, 'tcx, F> {
 
     pub region_highlight_mode: RegionHighlightMode<'tcx>,
 
-    pub name_resolver: Option<Box<&'a dyn Fn(ty::TyVid) -> Option<String>>>,
+    pub ty_infer_name_resolver: Option<Box<dyn Fn(ty::TyVid) -> Option<String> + 'a>>,
+    pub const_infer_name_resolver: Option<Box<dyn Fn(ty::ConstVid<'tcx>) -> Option<String> + 'a>>,
 }
 
 impl<'a, 'tcx, F> Deref for FmtPrinter<'a, 'tcx, F> {
@@ -1588,7 +1600,8 @@ impl<'a, 'tcx, F> FmtPrinter<'a, 'tcx, F> {
             binder_depth: 0,
             printed_type_count: 0,
             region_highlight_mode: RegionHighlightMode::new(tcx),
-            name_resolver: None,
+            ty_infer_name_resolver: None,
+            const_infer_name_resolver: None,
         }))
     }
 }
@@ -1843,8 +1856,12 @@ impl<'tcx, F: fmt::Write> Printer<'tcx> for FmtPrinter<'_, 'tcx, F> {
 }
 
 impl<'tcx, F: fmt::Write> PrettyPrinter<'tcx> for FmtPrinter<'_, 'tcx, F> {
-    fn infer_ty_name(&self, id: ty::TyVid) -> Option<String> {
-        self.0.name_resolver.as_ref().and_then(|func| func(id))
+    fn ty_infer_name(&self, id: ty::TyVid) -> Option<String> {
+        self.0.ty_infer_name_resolver.as_ref().and_then(|func| func(id))
+    }
+
+    fn const_infer_name(&self, id: ty::ConstVid<'tcx>) -> Option<String> {
+        self.0.const_infer_name_resolver.as_ref().and_then(|func| func(id))
     }
 
     fn print_value_path(
diff --git a/compiler/rustc_middle/src/ty/util.rs b/compiler/rustc_middle/src/ty/util.rs
index c2a4cea2b1a..92d9cb2fc1b 100644
--- a/compiler/rustc_middle/src/ty/util.rs
+++ b/compiler/rustc_middle/src/ty/util.rs
@@ -17,7 +17,7 @@ use rustc_data_structures::intern::Interned;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_errors::ErrorReported;
 use rustc_hir as hir;
-use rustc_hir::def::DefKind;
+use rustc_hir::def::{CtorOf, DefKind, Res};
 use rustc_hir::def_id::DefId;
 use rustc_macros::HashStable;
 use rustc_query_system::ich::NodeIdHashingMode;
@@ -146,6 +146,37 @@ impl<'tcx> TyCtxt<'tcx> {
         hasher.finish()
     }
 
+    pub fn res_generics_def_id(self, res: Res) -> Option<DefId> {
+        match res {
+            Res::Def(DefKind::Ctor(CtorOf::Variant, _), def_id) => {
+                Some(self.parent(def_id).and_then(|def_id| self.parent(def_id)).unwrap())
+            }
+            Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Struct, _), def_id) => {
+                Some(self.parent(def_id).unwrap())
+            }
+            // Other `DefKind`s don't have generics and would ICE when calling
+            // `generics_of`.
+            Res::Def(
+                DefKind::Struct
+                | DefKind::Union
+                | DefKind::Enum
+                | DefKind::Trait
+                | DefKind::OpaqueTy
+                | DefKind::TyAlias
+                | DefKind::ForeignTy
+                | DefKind::TraitAlias
+                | DefKind::AssocTy
+                | DefKind::Fn
+                | DefKind::AssocFn
+                | DefKind::AssocConst
+                | DefKind::Impl,
+                def_id,
+            ) => Some(def_id),
+            Res::Err => None,
+            _ => None,
+        }
+    }
+
     pub fn has_error_field(self, ty: Ty<'tcx>) -> bool {
         if let ty::Adt(def, substs) = *ty.kind() {
             for field in def.all_fields() {
diff --git a/compiler/rustc_typeck/src/collect/type_of.rs b/compiler/rustc_typeck/src/collect/type_of.rs
index cd7343a3211..39da7c82c4e 100644
--- a/compiler/rustc_typeck/src/collect/type_of.rs
+++ b/compiler/rustc_typeck/src/collect/type_of.rs
@@ -1,7 +1,6 @@
 use rustc_errors::{Applicability, ErrorReported, StashKey};
 use rustc_hir as hir;
-use rustc_hir::def::CtorOf;
-use rustc_hir::def::{DefKind, Res};
+use rustc_hir::def::Res;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::intravisit;
 use rustc_hir::intravisit::Visitor;
@@ -9,7 +8,7 @@ use rustc_hir::{HirId, Node};
 use rustc_middle::hir::nested_filter;
 use rustc_middle::ty::subst::InternalSubsts;
 use rustc_middle::ty::util::IntTypeExt;
-use rustc_middle::ty::{self, DefIdTree, Ty, TyCtxt, TypeFoldable, TypeFolder};
+use rustc_middle::ty::{self, Ty, TyCtxt, TypeFoldable, TypeFolder};
 use rustc_span::symbol::Ident;
 use rustc_span::{Span, DUMMY_SP};
 
@@ -198,38 +197,9 @@ pub(super) fn opt_const_param_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<
             // Try to use the segment resolution if it is valid, otherwise we
             // default to the path resolution.
             let res = segment.res.filter(|&r| r != Res::Err).unwrap_or(path.res);
-            let generics = match res {
-                Res::Def(DefKind::Ctor(CtorOf::Variant, _), def_id) => tcx
-                    .generics_of(tcx.parent(def_id).and_then(|def_id| tcx.parent(def_id)).unwrap()),
-                Res::Def(DefKind::Variant | DefKind::Ctor(CtorOf::Struct, _), def_id) => {
-                    tcx.generics_of(tcx.parent(def_id).unwrap())
-                }
-                // Other `DefKind`s don't have generics and would ICE when calling
-                // `generics_of`.
-                Res::Def(
-                    DefKind::Struct
-                    | DefKind::Union
-                    | DefKind::Enum
-                    | DefKind::Trait
-                    | DefKind::OpaqueTy
-                    | DefKind::TyAlias
-                    | DefKind::ForeignTy
-                    | DefKind::TraitAlias
-                    | DefKind::AssocTy
-                    | DefKind::Fn
-                    | DefKind::AssocFn
-                    | DefKind::AssocConst
-                    | DefKind::Impl,
-                    def_id,
-                ) => tcx.generics_of(def_id),
-                Res::Err => {
-                    tcx.sess.delay_span_bug(tcx.def_span(def_id), "anon const with Res::Err");
-                    return None;
-                }
-                _ => {
-                    // If the user tries to specify generics on a type that does not take them,
-                    // e.g. `usize<T>`, we may hit this branch, in which case we treat it as if
-                    // no arguments have been passed. An error should already have been emitted.
+            let generics = match tcx.res_generics_def_id(res) {
+                Some(def_id) => tcx.generics_of(def_id),
+                None => {
                     tcx.sess.delay_span_bug(
                         tcx.def_span(def_id),
                         &format!("unexpected anon const res {:?} in path: {:?}", res, path),
diff --git a/src/test/ui/const-generics/defaults/doesnt_infer.rs b/src/test/ui/const-generics/defaults/doesnt_infer.rs
index cd533b57bc3..9c59e672d8e 100644
--- a/src/test/ui/const-generics/defaults/doesnt_infer.rs
+++ b/src/test/ui/const-generics/defaults/doesnt_infer.rs
@@ -9,5 +9,5 @@ impl<const N: u32> Foo<N> {
 fn main() {
     let foo = Foo::<1>::foo();
     let foo = Foo::foo();
-    //~^ error: type annotations needed for `Foo<{_: u32}>`
+    //~^ error: type annotations needed for `Foo<N>`
 }
diff --git a/src/test/ui/const-generics/defaults/doesnt_infer.stderr b/src/test/ui/const-generics/defaults/doesnt_infer.stderr
index 1551e81ea75..cccf433e328 100644
--- a/src/test/ui/const-generics/defaults/doesnt_infer.stderr
+++ b/src/test/ui/const-generics/defaults/doesnt_infer.stderr
@@ -1,4 +1,4 @@
-error[E0282]: type annotations needed for `Foo<{_: u32}>`
+error[E0282]: type annotations needed for `Foo<N>`
   --> $DIR/doesnt_infer.rs:11:15
    |
 LL |     let foo = Foo::foo();
diff --git a/src/test/ui/const-generics/generic_arg_infer/issue-91614.rs b/src/test/ui/const-generics/generic_arg_infer/issue-91614.rs
index 413cc153924..b45e2cbc737 100644
--- a/src/test/ui/const-generics/generic_arg_infer/issue-91614.rs
+++ b/src/test/ui/const-generics/generic_arg_infer/issue-91614.rs
@@ -4,5 +4,5 @@ use std::simd::Mask;
 
 fn main() {
     let y = Mask::<_, _>::splat(false);
-    //~^ error: type annotations needed for `Mask<_, {_: usize}>`
+    //~^ ERROR: type annotations needed for
 }
diff --git a/src/test/ui/const-generics/generic_arg_infer/issue-91614.stderr b/src/test/ui/const-generics/generic_arg_infer/issue-91614.stderr
index 71a5ff79280..347cd2364b2 100644
--- a/src/test/ui/const-generics/generic_arg_infer/issue-91614.stderr
+++ b/src/test/ui/const-generics/generic_arg_infer/issue-91614.stderr
@@ -1,4 +1,4 @@
-error[E0283]: type annotations needed for `Mask<_, {_: usize}>`
+error[E0283]: type annotations needed for `Mask<_, LANES>`
   --> $DIR/issue-91614.rs:6:13
    |
 LL |     let y = Mask::<_, _>::splat(false);