Auto merge of #147957 - matthiaskrgr:rollup-aqt593u, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #141445 (Add `FromIterator` impls for `ascii::Char`s to `String`s)
 - #142339 (Add NonNull pattern types)
 - #147768 (Code refactoring on hir report_no_match_method_error)
 - #147788 (const Cell methods)
 - #147932 (Create UTF-8 version of `OsStr`/`OsString`)
 - #147933 (os_str: Make platform docs more consistent)
 - #147948 (PassWrapper: Access GlobalValueSummaryInfo::SummaryList via getter for LLVM 22+)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

compiler/rustc_ast/src/ast.rs

@@ -2579,6 +2579,9 @@ pub enum TyPatKind {
     /// A range pattern (e.g., `1...2`, `1..2`, `1..`, `..2`, `1..=2`, `..=2`).
     Range(Option<Box<AnonConst>>, Option<Box<AnonConst>>, Spanned<RangeEnd>),
 
+    /// A `!null` pattern for raw pointers.
+    NotNull,
+
     Or(ThinVec<TyPat>),
 
     /// Placeholder for a pattern that wasn't syntactically well formed in some way.

compiler/rustc_ast_lowering/src/pat.rs

@@ -143,7 +143,9 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                     }
                     // return inner to be processed in next loop
                     PatKind::Paren(inner) => pattern = inner,
-                    PatKind::MacCall(_) => panic!("{:?} shouldn't exist here", pattern.span),
+                    PatKind::MacCall(_) => {
+                        panic!("{pattern:#?} shouldn't exist here")
+                    }
                     PatKind::Err(guar) => break hir::PatKind::Err(*guar),
                 }
             };
@@ -460,6 +462,7 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
                         )
                     }),
             ),
+            TyPatKind::NotNull => hir::TyPatKind::NotNull,
             TyPatKind::Or(variants) => {
                 hir::TyPatKind::Or(self.arena.alloc_from_iter(
                     variants.iter().map(|pat| self.lower_ty_pat_mut(pat, base_type)),

compiler/rustc_ast_pretty/src/pprust/state.rs

@@ -1232,6 +1232,7 @@ impl<'a> State<'a> {
                     self.print_expr_anon_const(end, &[]);
                 }
             }
+            rustc_ast::TyPatKind::NotNull => self.word("!null"),
             rustc_ast::TyPatKind::Or(variants) => {
                 let mut first = true;
                 for pat in variants {

compiler/rustc_builtin_macros/src/pattern_type.rs

@@ -30,15 +30,21 @@ fn parse_pat_ty<'a>(
     let ty = parser.parse_ty()?;
     parser.expect_keyword(exp!(Is))?;
 
-    let pat = pat_to_ty_pat(
-        cx,
-        parser.parse_pat_no_top_guard(
-            None,
-            RecoverComma::No,
-            RecoverColon::No,
-            CommaRecoveryMode::EitherTupleOrPipe,
-        )?,
-    );
+    let start = parser.token.span;
+    let pat = if parser.eat(exp!(Bang)) {
+        parser.expect_keyword(exp!(Null))?;
+        ty_pat(TyPatKind::NotNull, start.to(parser.token.span))
+    } else {
+        pat_to_ty_pat(
+            cx,
+            parser.parse_pat_no_top_guard(
+                None,
+                RecoverComma::No,
+                RecoverColon::No,
+                CommaRecoveryMode::EitherTupleOrPipe,
+            )?,
+        )
+    };
 
     if parser.token != token::Eof {
         parser.unexpected()?;

compiler/rustc_codegen_cranelift/src/unsize.rs

@@ -131,6 +131,11 @@ pub(crate) fn coerce_unsized_into<'tcx>(
         dst.write_cvalue(fx, CValue::by_val_pair(base, info, dst.layout()));
     };
     match (&src_ty.kind(), &dst_ty.kind()) {
+        (ty::Pat(a, _), ty::Pat(b, _)) => {
+            let src = src.cast_pat_ty_to_base(fx.layout_of(*a));
+            let dst = dst.place_transmute_type(fx, *b);
+            return coerce_unsized_into(fx, src, dst);
+        }
         (&ty::Ref(..), &ty::Ref(..))
         | (&ty::Ref(..), &ty::RawPtr(..))
         | (&ty::RawPtr(..), &ty::RawPtr(..)) => coerce_ptr(),

compiler/rustc_codegen_cranelift/src/value_and_place.rs

@@ -342,6 +342,14 @@ impl<'tcx> CValue<'tcx> {
         assert_eq!(self.layout().backend_repr, layout.backend_repr);
         CValue(self.0, layout)
     }
+
+    pub(crate) fn cast_pat_ty_to_base(self, layout: TyAndLayout<'tcx>) -> Self {
+        let ty::Pat(base, _) = *self.layout().ty.kind() else {
+            panic!("not a pattern type: {:#?}", self.layout())
+        };
+        assert_eq!(layout.ty, base);
+        CValue(self.0, layout)
+    }
 }
 
 /// A place where you can write a value to or read a value from

compiler/rustc_codegen_ssa/src/base.rs

@@ -228,6 +228,7 @@ pub(crate) fn unsize_ptr<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>>(
 ) -> (Bx::Value, Bx::Value) {
     debug!("unsize_ptr: {:?} => {:?}", src_ty, dst_ty);
     match (src_ty.kind(), dst_ty.kind()) {
+        (&ty::Pat(a, _), &ty::Pat(b, _)) => unsize_ptr(bx, src, a, b, old_info),
         (&ty::Ref(_, a, _), &ty::Ref(_, b, _) | &ty::RawPtr(b, _))
         | (&ty::RawPtr(a, _), &ty::RawPtr(b, _)) => {
             assert_eq!(bx.cx().type_is_sized(a), old_info.is_none());

compiler/rustc_const_eval/src/interpret/cast.rs

@@ -466,6 +466,12 @@ impl<'tcx, M: Machine<'tcx>> InterpCx<'tcx, M> {
     ) -> InterpResult<'tcx> {
         trace!("Unsizing {:?} of type {} into {}", *src, src.layout.ty, cast_ty.ty);
         match (src.layout.ty.kind(), cast_ty.ty.kind()) {
+            (&ty::Pat(_, s_pat), &ty::Pat(cast_ty, c_pat)) if s_pat == c_pat => {
+                let src = self.project_field(src, FieldIdx::ZERO)?;
+                let dest = self.project_field(dest, FieldIdx::ZERO)?;
+                let cast_ty = self.layout_of(cast_ty)?;
+                self.unsize_into(&src, cast_ty, &dest)
+            }
             (&ty::Ref(_, s, _), &ty::Ref(_, c, _) | &ty::RawPtr(c, _))
             | (&ty::RawPtr(s, _), &ty::RawPtr(c, _)) => self.unsize_into_ptr(src, dest, s, c),
             (&ty::Adt(def_a, _), &ty::Adt(def_b, _)) => {

compiler/rustc_const_eval/src/interpret/validity.rs

@@ -1261,9 +1261,10 @@ impl<'rt, 'tcx, M: Machine<'tcx>> ValueVisitor<'tcx, M> for ValidityVisitor<'rt,
                 // When you extend this match, make sure to also add tests to
                 // tests/ui/type/pattern_types/validity.rs((
                 match **pat {
-                    // Range patterns are precisely reflected into `valid_range` and thus
+                    // Range and non-null patterns are precisely reflected into `valid_range` and thus
                     // handled fully by `visit_scalar` (called below).
                     ty::PatternKind::Range { .. } => {},
+                    ty::PatternKind::NotNull => {},
 
                     // FIXME(pattern_types): check that the value is covered by one of the variants.
                     // For now, we rely on layout computation setting the scalar's `valid_range` to

compiler/rustc_hir/src/hir.rs

@@ -1854,6 +1854,9 @@ pub enum TyPatKind<'hir> {
     /// A range pattern (e.g., `1..=2` or `1..2`).
     Range(&'hir ConstArg<'hir>, &'hir ConstArg<'hir>),
 
+    /// A pattern that excludes null pointers
+    NotNull,
+
     /// A list of patterns where only one needs to be satisfied
     Or(&'hir [TyPat<'hir>]),