Thread pattern types through the HIR

compiler/rustc_ast_lowering/src/lib.rs

@@ -1531,7 +1531,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                 );
                 hir::TyKind::Err(guar)
             }
-            TyKind::Pat(..) => span_bug!(t.span, "pattern types are unimplemented"),
+            TyKind::Pat(ty, pat) => hir::TyKind::Pat(self.lower_ty(ty, itctx), self.lower_pat(pat)),
         };
 
         hir::Ty { kind, span: self.lower_span(t.span), hir_id: self.lower_node_id(t.id) }

compiler/rustc_hir/src/hir.rs

@@ -2621,6 +2621,8 @@ pub enum TyKind<'hir> {
     Infer,
     /// Placeholder for a type that has failed to be defined.
     Err(rustc_span::ErrorGuaranteed),
+    /// Pattern types (`u32 as 1..`)
+    Pat(&'hir Ty<'hir>, &'hir Pat<'hir>),
 }
 
 #[derive(Debug, Clone, Copy, HashStable_Generic)]

compiler/rustc_hir/src/intravisit.rs

@@ -857,6 +857,10 @@ pub fn walk_ty<'v, V: Visitor<'v>>(visitor: &mut V, typ: &'v Ty<'v>) {
         }
         TyKind::Typeof(ref expression) => visitor.visit_anon_const(expression),
         TyKind::Infer | TyKind::InferDelegation(..) | TyKind::Err(_) => {}
+        TyKind::Pat(ty, pat) => {
+            visitor.visit_ty(ty);
+            visitor.visit_pat(pat)
+        }
     }
 }
 

compiler/rustc_hir_analysis/src/astconv/mod.rs

@@ -2559,6 +2559,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 // handled specially and will not descend into this routine.
                 self.ty_infer(None, ast_ty.span)
             }
+            hir::TyKind::Pat(..) => span_bug!(ast_ty.span, "{ast_ty:#?}"),
             hir::TyKind::Err(guar) => Ty::new_error(tcx, *guar),
         };
 

compiler/rustc_hir_pretty/src/lib.rs

@@ -323,6 +323,11 @@ impl<'a> State<'a> {
             hir::TyKind::Infer | hir::TyKind::InferDelegation(..) => {
                 self.word("_");
             }
+            hir::TyKind::Pat(ty, pat) => {
+                self.print_type(ty);
+                self.word(" is ");
+                self.print_pat(pat);
+            }
         }
         self.end()
     }

compiler/rustc_passes/src/hir_stats.rs

@@ -355,6 +355,7 @@ impl<'v> hir_visit::Visitor<'v> for StatCollector<'v> {
                 TraitObject,
                 Typeof,
                 Infer,
+                Pat,
                 Err
             ]
         );

src/librustdoc/clean/mod.rs

@@ -1833,6 +1833,7 @@ pub(crate) fn clean_ty<'tcx>(ty: &hir::Ty<'tcx>, cx: &mut DocContext<'tcx>) -> T
             BorrowedRef { lifetime, mutability: m.mutbl, type_: Box::new(clean_ty(m.ty, cx)) }
         }
         TyKind::Slice(ty) => Slice(Box::new(clean_ty(ty, cx))),
+        TyKind::Pat(ty, pat) => Type::Pat(Box::new(clean_ty(ty, cx)), format!("{pat:?}").into()),
         TyKind::Array(ty, ref length) => {
             let length = match length {
                 hir::ArrayLen::Infer(_, _) => "_".to_string(),

src/librustdoc/clean/types.rs

@@ -1481,7 +1481,9 @@ pub(crate) enum Type {
     ///
     /// This is mostly Rustdoc's version of [`hir::Path`].
     /// It has to be different because Rustdoc's [`PathSegment`] can contain cleaned generics.
-    Path { path: Path },
+    Path {
+        path: Path,
+    },
     /// A `dyn Trait` object: `dyn for<'a> Trait<'a> + Send + 'static`
     DynTrait(Vec<PolyTrait>, Option<Lifetime>),
     /// A type parameter.
@@ -1498,10 +1500,15 @@ pub(crate) enum Type {
     ///
     /// The `String` field is a stringified version of the array's length parameter.
     Array(Box<Type>, Box<str>),
+    Pat(Box<Type>, Box<str>),
     /// A raw pointer type: `*const i32`, `*mut i32`
     RawPointer(Mutability, Box<Type>),
     /// A reference type: `&i32`, `&'a mut Foo`
-    BorrowedRef { lifetime: Option<Lifetime>, mutability: Mutability, type_: Box<Type> },
+    BorrowedRef {
+        lifetime: Option<Lifetime>,
+        mutability: Mutability,
+        type_: Box<Type>,
+    },
 
     /// A qualified path to an associated item: `<Type as Trait>::Name`
     QPath(Box<QPathData>),
@@ -1698,6 +1705,7 @@ impl Type {
             BareFunction(..) => PrimitiveType::Fn,
             Slice(..) => PrimitiveType::Slice,
             Array(..) => PrimitiveType::Array,
+            Type::Pat(..) => PrimitiveType::Pat,
             RawPointer(..) => PrimitiveType::RawPointer,
             QPath(box QPathData { ref self_type, .. }) => return self_type.inner_def_id(cache),
             Generic(_) | Infer | ImplTrait(_) => return None,
@@ -1749,6 +1757,7 @@ pub(crate) enum PrimitiveType {
     Str,
     Slice,
     Array,
+    Pat,
     Tuple,
     Unit,
     RawPointer,
@@ -1895,6 +1904,7 @@ impl PrimitiveType {
             Bool => sym::bool,
             Char => sym::char,
             Array => sym::array,
+            Pat => sym::pat,
             Slice => sym::slice,
             Tuple => sym::tuple,
             Unit => sym::unit,

src/librustdoc/html/format.rs

@@ -1060,6 +1060,10 @@ fn fmt_type<'cx>(
                 write!(f, "]")
             }
         },
+        clean::Type::Pat(ref t, ref pat) => {
+            fmt::Display::fmt(&t.print(cx), f)?;
+            write!(f, " is {pat}")
+        }
         clean::Array(ref t, ref n) => match **t {
             clean::Generic(name) if !f.alternate() => primitive_link(
                 f,

src/librustdoc/html/render/search_index.rs

@@ -584,7 +584,11 @@ fn get_index_type_id(
             }
         }
         // Not supported yet
-        clean::BareFunction(_) | clean::Generic(_) | clean::ImplTrait(_) | clean::Infer => None,
+        clean::Type::Pat(..)
+        | clean::BareFunction(_)
+        | clean::Generic(_)
+        | clean::ImplTrait(_)
+        | clean::Infer => None,
     }
 }
 

src/librustdoc/json/conversions.rs

@@ -576,6 +576,9 @@ impl FromWithTcx<clean::Type> for Type {
             Tuple(t) => Type::Tuple(t.into_tcx(tcx)),
             Slice(t) => Type::Slice(Box::new((*t).into_tcx(tcx))),
             Array(t, s) => Type::Array { type_: Box::new((*t).into_tcx(tcx)), len: s.to_string() },
+            clean::Type::Pat(t, p) => {
+                Type::Pat { type_: Box::new((*t).into_tcx(tcx)), pat: p.to_string() }
+            }
             ImplTrait(g) => Type::ImplTrait(g.into_tcx(tcx)),
             Infer => Type::Infer,
             RawPointer(mutability, type_) => Type::RawPointer {

src/rustdoc-json-types/lib.rs

@@ -8,7 +8,7 @@ use serde::{Deserialize, Serialize};
 use std::path::PathBuf;
 
 /// rustdoc format-version.
-pub const FORMAT_VERSION: u32 = 28;
+pub const FORMAT_VERSION: u32 = 29;
 
 /// A `Crate` is the root of the emitted JSON blob. It contains all type/documentation information
 /// about the language items in the local crate, as well as info about external items to allow
@@ -562,6 +562,12 @@ pub enum Type {
         type_: Box<Type>,
         len: String,
     },
+    /// `u32 is 1..`
+    Pat {
+        #[serde(rename = "type")]
+        type_: Box<Type>,
+        pat: String,
+    },
     /// `impl TraitA + TraitB + ...`
     ImplTrait(Vec<GenericBound>),
     /// `_`

src/tools/clippy/clippy_lints/src/dereference.rs

@@ -823,6 +823,7 @@ impl TyCoercionStability {
                 | TyKind::Array(..)
                 | TyKind::Ptr(_)
                 | TyKind::BareFn(_)
+                | TyKind::Pat(..)
                 | TyKind::Never
                 | TyKind::Tup(_)
                 | TyKind::Path(_) => Self::Deref,

src/tools/clippy/clippy_utils/src/hir_utils.rs

@@ -1068,6 +1068,10 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
                 self.hash_ty(ty);
                 self.hash_array_length(len);
             },
+            TyKind::Pat(ty, pat) => {
+                self.hash_ty(ty);
+                self.hash_pat(pat);
+            },
             TyKind::Ptr(ref mut_ty) => {
                 self.hash_ty(mut_ty.ty);
                 mut_ty.mutbl.hash(&mut self.s);