Add NonNull pattern types

compiler/rustc_ast/src/ast.rs

@@ -2632,6 +2632,9 @@ pub enum TyPatKind {
     /// A range pattern (e.g., `1...2`, `1..2`, `1..`, `..2`, `1..=2`, `..=2`).
     Range(Option<P<AnonConst>>, Option<P<AnonConst>>, Spanned<RangeEnd>),
 
+    /// A `!null` pattern for raw pointers.
+    NotNull,
+
     Or(ThinVec<P<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

@@ -1234,6 +1234,7 @@ 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

@@ -28,15 +28,21 @@ fn parse_pat_ty<'a>(cx: &mut ExtCtxt<'a>, stream: TokenStream) -> PResult<'a, (P
     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_const_eval/src/interpret/validity.rs

@@ -1259,9 +1259,10 @@ 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

@@ -1830,6 +1830,9 @@ 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>]),
 

compiler/rustc_hir/src/intravisit.rs

@@ -731,7 +731,7 @@ pub fn walk_ty_pat<'v, V: Visitor<'v>>(visitor: &mut V, pattern: &'v TyPat<'v>)
             try_visit!(visitor.visit_const_arg_unambig(upper_bound));
         }
         TyPatKind::Or(patterns) => walk_list!(visitor, visit_pattern_type_pattern, patterns),
-        TyPatKind::Err(_) => (),
+        TyPatKind::NotNull | TyPatKind::Err(_) => (),
     }
     V::Result::output()
 }

compiler/rustc_hir_analysis/src/hir_ty_lowering/mod.rs

@@ -2593,6 +2593,7 @@ impl<'tcx> dyn HirTyLowerer<'tcx> + '_ {
                         .span_delayed_bug(ty_span, "invalid base type for range pattern")),
                 }
             }
+            hir::TyPatKind::NotNull => Ok(ty::PatternKind::NotNull),
             hir::TyPatKind::Or(patterns) => {
                 self.tcx()
                     .mk_patterns_from_iter(patterns.iter().map(|pat| {

compiler/rustc_hir_analysis/src/variance/constraints.rs

@@ -340,6 +340,7 @@ impl<'a, 'tcx> ConstraintContext<'a, 'tcx> {
                 self.add_constraints_from_const(current, start, variance);
                 self.add_constraints_from_const(current, end, variance);
             }
+            ty::PatternKind::NotNull => {}
             ty::PatternKind::Or(patterns) => {
                 for pat in patterns {
                     self.add_constraints_from_pat(current, variance, pat)

compiler/rustc_hir_pretty/src/lib.rs

@@ -1883,6 +1883,10 @@ impl<'a> State<'a> {
                 self.word("..=");
                 self.print_const_arg(end);
             }
+            TyPatKind::NotNull => {
+                self.word_space("not");
+                self.word("null");
+            }
             TyPatKind::Or(patterns) => {
                 self.popen();
                 let mut first = true;

compiler/rustc_lint/src/types.rs

@@ -904,6 +904,7 @@ fn pat_ty_is_known_nonnull<'tcx>(
                     // to ensure we aren't wrapping over zero.
                     start > 0 && end >= start
                 }
+                ty::PatternKind::NotNull => true,
                 ty::PatternKind::Or(patterns) => {
                     patterns.iter().all(|pat| pat_ty_is_known_nonnull(tcx, typing_env, pat))
                 }
@@ -1065,7 +1066,9 @@ fn get_nullable_type_from_pat<'tcx>(
     pat: ty::Pattern<'tcx>,
 ) -> Option<Ty<'tcx>> {
     match *pat {
-        ty::PatternKind::Range { .. } => get_nullable_type(tcx, typing_env, base),
+        ty::PatternKind::NotNull | ty::PatternKind::Range { .. } => {
+            get_nullable_type(tcx, typing_env, base)
+        }
         ty::PatternKind::Or(patterns) => {
             let first = get_nullable_type_from_pat(tcx, typing_env, base, patterns[0])?;
             for &pat in &patterns[1..] {

compiler/rustc_middle/src/ty/pattern.rs

@@ -30,6 +30,7 @@ impl<'tcx> Flags for Pattern<'tcx> {
                 }
                 flags
             }
+            ty::PatternKind::NotNull => rustc_type_ir::TypeFlags::empty(),
         }
     }
 
@@ -45,6 +46,7 @@ impl<'tcx> Flags for Pattern<'tcx> {
                 }
                 idx
             }
+            ty::PatternKind::NotNull => rustc_type_ir::INNERMOST,
         }
     }
 }
@@ -91,6 +93,7 @@ impl<'tcx> IrPrint<PatternKind<'tcx>> for TyCtxt<'tcx> {
 
                 write!(f, "..={end}")
             }
+            PatternKind::NotNull => write!(f, "!null"),
             PatternKind::Or(patterns) => {
                 write!(f, "(")?;
                 let mut first = true;

compiler/rustc_middle/src/ty/relate.rs

@@ -59,6 +59,7 @@ impl<'tcx> Relate<TyCtxt<'tcx>> for ty::Pattern<'tcx> {
                 let end = relation.relate(end_a, end_b)?;
                 Ok(tcx.mk_pat(ty::PatternKind::Range { start, end }))
             }
+            (ty::PatternKind::NotNull, ty::PatternKind::NotNull) => Ok(a),
             (&ty::PatternKind::Or(a), &ty::PatternKind::Or(b)) => {
                 if a.len() != b.len() {
                     return Err(TypeError::Mismatch);
@@ -67,7 +68,10 @@ impl<'tcx> Relate<TyCtxt<'tcx>> for ty::Pattern<'tcx> {
                 let patterns = tcx.mk_patterns_from_iter(v)?;
                 Ok(tcx.mk_pat(ty::PatternKind::Or(patterns)))
             }
-            (ty::PatternKind::Range { .. } | ty::PatternKind::Or(_), _) => Err(TypeError::Mismatch),
+            (
+                ty::PatternKind::NotNull | ty::PatternKind::Range { .. } | ty::PatternKind::Or(_),
+                _,
+            ) => Err(TypeError::Mismatch),
         }
     }
 }

compiler/rustc_parse/src/parser/token_type.rs

@@ -139,6 +139,7 @@ pub enum TokenType {
     SymNomem,
     SymNoreturn,
     SymNostack,
+    SymNull,
     SymOptions,
     SymOut,
     SymPreservesFlags,
@@ -273,6 +274,7 @@ impl TokenType {
             SymNomem,
             SymNoreturn,
             SymNostack,
+            SymNull,
             SymOptions,
             SymOut,
             SymPreservesFlags,
@@ -348,6 +350,7 @@ impl TokenType {
             TokenType::SymNomem => Some(sym::nomem),
             TokenType::SymNoreturn => Some(sym::noreturn),
             TokenType::SymNostack => Some(sym::nostack),
+            TokenType::SymNull => Some(sym::null),
             TokenType::SymOptions => Some(sym::options),
             TokenType::SymOut => Some(sym::out),
             TokenType::SymPreservesFlags => Some(sym::preserves_flags),
@@ -562,6 +565,7 @@ macro_rules! exp {
     (Nomem)          => { exp!(@sym, nomem,           SymNomem) };
     (Noreturn)       => { exp!(@sym, noreturn,        SymNoreturn) };
     (Nostack)        => { exp!(@sym, nostack,         SymNostack) };
+    (Null)           => { exp!(@sym, null,            SymNull) };
     (Options)        => { exp!(@sym, options,         SymOptions) };
     (Out)            => { exp!(@sym, out,             SymOut) };
     (PreservesFlags) => { exp!(@sym, preserves_flags, SymPreservesFlags) };

compiler/rustc_public/src/unstable/convert/stable/ty.rs

@@ -496,6 +496,7 @@ impl<'tcx> Stable<'tcx> for ty::Pattern<'tcx> {
                 end: Some(end.stable(tables, cx)),
                 include_end: true,
             },
+            ty::PatternKind::NotNull => todo!(),
             ty::PatternKind::Or(_) => todo!(),
         }
     }

compiler/rustc_resolve/src/late.rs

@@ -976,7 +976,7 @@ impl<'ast, 'ra, 'tcx> Visitor<'ast> for LateResolutionVisitor<'_, 'ast, 'ra, 'tc
                     self.visit_ty_pat(pat)
                 }
             }
-            TyPatKind::Err(_) => {}
+            TyPatKind::NotNull | TyPatKind::Err(_) => {}
         }
     }
 

compiler/rustc_span/src/symbol.rs

@@ -1512,6 +1512,7 @@ symbols! {
         not,
         notable_trait,
         note,
+        null,
         object_safe_for_dispatch,
         of,
         off,

compiler/rustc_symbol_mangling/src/v0.rs

@@ -263,6 +263,9 @@ impl<'tcx> SymbolMangler<'tcx> {
                     Ty::new_array_with_const_len(self.tcx, self.tcx.types.unit, ct).print(self)?;
                 }
             }
+            ty::PatternKind::NotNull => {
+                self.tcx.types.unit.print(self)?;
+            }
             ty::PatternKind::Or(patterns) => {
                 for pat in patterns {
                     self.print_pat(pat)?;

compiler/rustc_trait_selection/src/traits/wf.rs

@@ -705,6 +705,7 @@ impl<'a, 'tcx> WfPredicates<'a, 'tcx> {
                 check(start);
                 check(end);
             }
+            ty::PatternKind::NotNull => {}
             ty::PatternKind::Or(patterns) => {
                 for pat in patterns {
                     self.add_wf_preds_for_pat_ty(base_ty, pat)

compiler/rustc_ty_utils/src/layout.rs

@@ -213,9 +213,7 @@ fn layout_of_uncached<'tcx>(
             let mut layout = LayoutData::clone(&layout.0);
             match *pat {
                 ty::PatternKind::Range { start, end } => {
-                    if let BackendRepr::Scalar(scalar) | BackendRepr::ScalarPair(scalar, _) =
-                        &mut layout.backend_repr
-                    {
+                    if let BackendRepr::Scalar(scalar) = &mut layout.backend_repr {
                         scalar.valid_range_mut().start = extract_const_value(cx, ty, start)?
                             .try_to_bits(tcx, cx.typing_env)
                             .ok_or_else(|| error(cx, LayoutError::Unknown(ty)))?;
@@ -263,6 +261,25 @@ fn layout_of_uncached<'tcx>(
                         bug!("pattern type with range but not scalar layout: {ty:?}, {layout:?}")
                     }
                 }
+                ty::PatternKind::NotNull => {
+                    if let BackendRepr::Scalar(scalar) | BackendRepr::ScalarPair(scalar, _) =
+                        &mut layout.backend_repr
+                    {
+                        scalar.valid_range_mut().start = 1;
+                        let niche = Niche {
+                            offset: Size::ZERO,
+                            value: scalar.primitive(),
+                            valid_range: scalar.valid_range(cx),
+                        };
+
+                        layout.largest_niche = Some(niche);
+                    } else {
+                        bug!(
+                            "pattern type with `!null` pattern but not scalar/pair layout: {ty:?}, {layout:?}"
+                        )
+                    }
+                }
+
                 ty::PatternKind::Or(variants) => match *variants[0] {
                     ty::PatternKind::Range { .. } => {
                         if let BackendRepr::Scalar(scalar) = &mut layout.backend_repr {
@@ -279,7 +296,7 @@ fn layout_of_uncached<'tcx>(
                                             .try_to_bits(tcx, cx.typing_env)
                                             .ok_or_else(|| error(cx, LayoutError::Unknown(ty)))?,
                                     )),
-                                    ty::PatternKind::Or(_) => {
+                                    ty::PatternKind::NotNull | ty::PatternKind::Or(_) => {
                                         unreachable!("mixed or patterns are not allowed")
                                     }
                                 })
@@ -344,6 +361,7 @@ fn layout_of_uncached<'tcx>(
                             )
                         }
                     }
+                    ty::PatternKind::NotNull => bug!("or patterns can't contain `!null` patterns"),
                     ty::PatternKind::Or(..) => bug!("patterns cannot have nested or patterns"),
                 },
             }

compiler/rustc_type_ir/src/pattern.rs

@@ -14,4 +14,5 @@ use crate::Interner;
 pub enum PatternKind<I: Interner> {
     Range { start: I::Const, end: I::Const },
     Or(I::PatList),
+    NotNull,
 }

compiler/rustc_type_ir/src/walk.rs

@@ -178,5 +178,6 @@ fn push_ty_pat<I: Interner>(stack: &mut TypeWalkerStack<I>, pat: I::Pat) {
                 push_ty_pat::<I>(stack, pat)
             }
         }
+        ty::PatternKind::NotNull => {}
     }
 }

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

@@ -1121,7 +1121,7 @@ impl<'a, 'tcx> SpanlessHash<'a, 'tcx> {
                     self.hash_ty_pat(variant);
                 }
             },
-            TyPatKind::Err(_) => {},
+            TyPatKind::NotNull | TyPatKind::Err(_) => {},
         }
     }
 

src/tools/rustfmt/src/types.rs

@@ -1100,7 +1100,7 @@ impl Rewrite for ast::TyPat {
                 }
                 Ok(s)
             }
-            ast::TyPatKind::Err(_) => Err(RewriteError::Unknown),
+            ast::TyPatKind::NotNull | ast::TyPatKind::Err(_) => Err(RewriteError::Unknown),
         }
     }
 }

tests/ui/type/pattern_types/bad_pat.rs

@@ -10,4 +10,15 @@ type Positive2 = pattern_type!(i32 is 0..=);
 type Wild = pattern_type!(() is _);
 //~^ ERROR: pattern not supported in pattern types
 
+// FIXME: confusing diagnostic because `not` can be a binding
+type NonNull = pattern_type!(*const () is not null);
+//~^ ERROR: expected one of `@` or `|`, found `null`
+//~| ERROR: pattern not supported in pattern types
+
+type NonNull2 = pattern_type!(*const () is !nil);
+//~^ ERROR: expected `null`, found `nil`
+
+// FIXME: reject with a type mismatch
+type Mismatch2 = pattern_type!(() is !null);
+
 fn main() {}

tests/ui/type/pattern_types/bad_pat.stderr

@@ -30,6 +30,24 @@ error: pattern not supported in pattern types
 LL | type Wild = pattern_type!(() is _);
    |                                 ^
 
-error: aborting due to 3 previous errors
+error: pattern not supported in pattern types
+  --> $DIR/bad_pat.rs:14:43
+   |
+LL | type NonNull = pattern_type!(*const () is not null);
+   |                                           ^^^
+
+error: expected one of `@` or `|`, found `null`
+  --> $DIR/bad_pat.rs:14:47
+   |
+LL | type NonNull = pattern_type!(*const () is not null);
+   |                                               ^^^^ expected one of `@` or `|`
+
+error: expected `null`, found `nil`
+  --> $DIR/bad_pat.rs:18:45
+   |
+LL | type NonNull2 = pattern_type!(*const () is !nil);
+   |                                             ^^^ expected `null`
+
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0586`.