Allow initializing NonZero with literals

oli-obk · oli-obk · commit 8797188c9e30 · 2025-07-08T06:40:03.000Z
diff --git a/compiler/rustc_hir/src/lang_items.rs b/compiler/rustc_hir/src/lang_items.rs
@@ -426,6 +426,8 @@ language_item_table! {
     String,                  sym::String,              string,                     Target::Struct,         GenericRequirement::None;
     CStr,                    sym::CStr,                c_str,                      Target::Struct,         GenericRequirement::None;
 
+    NonZero,                 sym::NonZero,             non_zero,                   Target::Struct,         GenericRequirement::Exact(1);
+
     // Experimental lang items for implementing contract pre- and post-condition checking.
     ContractBuildCheckEnsures, sym::contract_build_check_ensures, contract_build_check_ensures_fn, Target::Fn, GenericRequirement::None;
     ContractCheckRequires,     sym::contract_check_requires,      contract_check_requires_fn,      Target::Fn, GenericRequirement::None;
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
@@ -1665,6 +1665,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                             _ => unreachable!(),
                         }
                     }
+                    ty::Adt(adt, ..) if tcx.is_lang_item(adt.did(), LangItem::NonZero) => {
+                        if i.get() == 0 {
+                            // FIXME: report a nice error
+                            None
+                        } else {
+                            Some(ty)
+                        }
+                    }
                     _ => None,
                 });
                 opt_ty.unwrap_or_else(|| self.next_int_var())
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
@@ -2487,7 +2487,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             _ => return false,
         };
 
-        if !self.tcx.is_diagnostic_item(sym::NonZero, adt.did()) {
+        if !self.tcx.is_lang_item(adt.did(), LangItem::NonZero) {
             return false;
         }
 
diff --git a/compiler/rustc_lint/src/lints.rs b/compiler/rustc_lint/src/lints.rs
@@ -12,7 +12,7 @@ use rustc_hir as hir;
 use rustc_hir::def::Namespace;
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::VisitorExt;
-use rustc_macros::{LintDiagnostic, Subdiagnostic};
+use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
 use rustc_middle::ty::inhabitedness::InhabitedPredicate;
 use rustc_middle::ty::{Clause, PolyExistentialTraitRef, Ty, TyCtxt};
 use rustc_session::Session;
@@ -1714,6 +1714,19 @@ pub(crate) struct OverflowingInt<'a> {
     #[subdiagnostic]
     pub help: Option<OverflowingIntHelp<'a>>,
 }
+#[derive(Diagnostic)]
+#[diag(lint_overflowing_int)]
+#[note]
+pub(crate) struct OverflowingIntError<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub ty: &'a str,
+    pub lit: String,
+    pub min: i128,
+    pub max: u128,
+    #[subdiagnostic]
+    pub help: Option<OverflowingIntHelp<'a>>,
+}
 
 #[derive(Subdiagnostic)]
 #[help(lint_help)]
@@ -1739,6 +1752,18 @@ pub(crate) struct OverflowingUInt<'a> {
     pub max: u128,
 }
 
+#[derive(Diagnostic)]
+#[diag(lint_overflowing_uint)]
+#[note]
+pub(crate) struct OverflowingUIntError<'a> {
+    #[primary_span]
+    pub span: Span,
+    pub ty: &'a str,
+    pub lit: String,
+    pub min: u128,
+    pub max: u128,
+}
+
 #[derive(LintDiagnostic)]
 #[diag(lint_overflowing_literal)]
 #[note]
diff --git a/compiler/rustc_lint/src/types/literal.rs b/compiler/rustc_lint/src/types/literal.rs
@@ -11,8 +11,9 @@ use crate::LateContext;
 use crate::context::LintContext;
 use crate::lints::{
     OnlyCastu8ToChar, OverflowingBinHex, OverflowingBinHexSign, OverflowingBinHexSignBitSub,
-    OverflowingBinHexSub, OverflowingInt, OverflowingIntHelp, OverflowingLiteral, OverflowingUInt,
-    RangeEndpointOutOfRange, UseInclusiveRange,
+    OverflowingBinHexSub, OverflowingInt, OverflowingIntError, OverflowingIntHelp,
+    OverflowingLiteral, OverflowingUInt, OverflowingUIntError, RangeEndpointOutOfRange,
+    UseInclusiveRange,
 };
 use crate::types::{OVERFLOWING_LITERALS, TypeLimits};
 
@@ -250,6 +251,7 @@ fn lint_int_literal<'tcx>(
     lit: &hir::Lit,
     t: ty::IntTy,
     v: u128,
+    force_error: bool,
 ) {
     let int_type = t.normalize(cx.sess().target.pointer_width);
     let (min, max) = int_ty_range(int_type);
@@ -287,11 +289,22 @@ fn lint_int_literal<'tcx>(
         let help = get_type_suggestion(cx.typeck_results().node_type(hir_id), v, negative)
             .map(|suggestion_ty| OverflowingIntHelp { suggestion_ty });
 
-        cx.emit_span_lint(
-            OVERFLOWING_LITERALS,
-            span,
-            OverflowingInt { ty: t.name_str(), lit, min, max, help },
-        );
+        if force_error {
+            cx.tcx.dcx().emit_err(OverflowingIntError {
+                span,
+                ty: t.name_str(),
+                lit,
+                min,
+                max,
+                help,
+            });
+        } else {
+            cx.emit_span_lint(
+                OVERFLOWING_LITERALS,
+                span,
+                OverflowingInt { ty: t.name_str(), lit, min, max, help },
+            );
+        }
     }
 }
 
@@ -301,6 +314,7 @@ fn lint_uint_literal<'tcx>(
     span: Span,
     lit: &hir::Lit,
     t: ty::UintTy,
+    force_error: bool,
 ) {
     let uint_type = t.normalize(cx.sess().target.pointer_width);
     let (min, max) = uint_ty_range(uint_type);
@@ -344,10 +358,9 @@ fn lint_uint_literal<'tcx>(
             );
             return;
         }
-        cx.emit_span_lint(
-            OVERFLOWING_LITERALS,
-            span,
-            OverflowingUInt {
+        if force_error {
+            cx.tcx.dcx().emit_err(OverflowingUIntError {
+                span,
                 ty: t.name_str(),
                 lit: cx
                     .sess()
@@ -356,8 +369,23 @@ fn lint_uint_literal<'tcx>(
                     .unwrap_or_else(|_| lit_val.to_string()),
                 min,
                 max,
-            },
-        );
+            });
+        } else {
+            cx.emit_span_lint(
+                OVERFLOWING_LITERALS,
+                span,
+                OverflowingUInt {
+                    ty: t.name_str(),
+                    lit: cx
+                        .sess()
+                        .source_map()
+                        .span_to_snippet(lit.span)
+                        .unwrap_or_else(|_| lit_val.to_string()),
+                    min,
+                    max,
+                },
+            );
+        }
     }
 }
 
@@ -369,18 +397,39 @@ pub(crate) fn lint_literal<'tcx>(
     lit: &hir::Lit,
     negated: bool,
 ) {
-    match *cx.typeck_results().node_type(hir_id).kind() {
+    lint_literal_inner(
+        cx,
+        type_limits,
+        hir_id,
+        cx.typeck_results().node_type(hir_id),
+        span,
+        lit,
+        negated,
+        false,
+    )
+}
+pub(crate) fn lint_literal_inner<'tcx>(
+    cx: &LateContext<'tcx>,
+    type_limits: &TypeLimits,
+    hir_id: HirId,
+    ty: Ty<'tcx>,
+    span: Span,
+    lit: &hir::Lit,
+    negated: bool,
+    force_error: bool,
+) {
+    match *ty.kind() {
         ty::Int(t) => {
             match lit.node {
                 ast::LitKind::Int(v, ast::LitIntType::Signed(_) | ast::LitIntType::Unsuffixed) => {
-                    lint_int_literal(cx, type_limits, hir_id, span, lit, t, v.get())
+                    lint_int_literal(cx, type_limits, hir_id, span, lit, t, v.get(), force_error)
                 }
                 _ => bug!(),
             };
         }
         ty::Uint(t) => {
             assert!(!negated);
-            lint_uint_literal(cx, hir_id, span, lit, t)
+            lint_uint_literal(cx, hir_id, span, lit, t, force_error)
         }
         ty::Float(t) => {
             let (is_infinite, sym) = match lit.node {
@@ -409,6 +458,12 @@ pub(crate) fn lint_literal<'tcx>(
                 );
             }
         }
+        ty::Pat(base, ..) if base.is_integral() => {
+            lint_literal_inner(cx, type_limits, hir_id, base, span, lit, negated, true)
+        }
+        ty::Adt(adt, args) if cx.tcx.is_lang_item(adt.did(), hir::LangItem::NonZero) => {
+            lint_literal_inner(cx, type_limits, hir_id, args.type_at(0), span, lit, negated, true)
+        }
         _ => {}
     }
 }
diff --git a/compiler/rustc_mir_build/src/builder/expr/as_constant.rs b/compiler/rustc_mir_build/src/builder/expr/as_constant.rs
@@ -107,6 +107,7 @@ fn lit_to_mir_constant<'tcx>(tcx: TyCtxt<'tcx>, lit_input: LitToConstInput<'tcx>
 
     let lit_ty = match *ty.kind() {
         ty::Pat(base, _) => base,
+        ty::Adt(adt, args) if tcx.is_lang_item(adt.did(), LangItem::NonZero) => args.type_at(0),
         _ => ty,
     };
 
diff --git a/library/core/src/num/nonzero.rs b/library/core/src/num/nonzero.rs
@@ -114,7 +114,7 @@ impl_zeroable_primitive!(
 #[stable(feature = "generic_nonzero", since = "1.79.0")]
 #[repr(transparent)]
 #[rustc_nonnull_optimization_guaranteed]
-#[rustc_diagnostic_item = "NonZero"]
+#[lang = "NonZero"]
 pub struct NonZero<T: ZeroablePrimitive>(T::NonZeroInner);
 
 macro_rules! impl_nonzero_fmt {
diff --git a/src/tools/clippy/clippy_lints/src/methods/useless_nonzero_new_unchecked.rs b/src/tools/clippy/clippy_lints/src/methods/useless_nonzero_new_unchecked.rs
@@ -2,9 +2,9 @@ use clippy_utils::diagnostics::{span_lint_and_sugg, span_lint_and_then};
 use clippy_utils::is_inside_always_const_context;
 use clippy_utils::msrvs::{self, Msrv};
 use clippy_utils::source::snippet_with_applicability;
-use clippy_utils::ty::is_type_diagnostic_item;
+use clippy_utils::ty::is_type_lang_item;
 use rustc_errors::Applicability;
-use rustc_hir::{Block, BlockCheckMode, Expr, ExprKind, Node, QPath, UnsafeSource};
+use rustc_hir::{Block, BlockCheckMode, Expr, ExprKind, LangItem, Node, QPath, UnsafeSource};
 use rustc_lint::LateContext;
 use rustc_span::sym;
 
@@ -15,7 +15,7 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &Expr<'_>, func: &Expr<'
         && segment.ident.name == sym::new_unchecked
         && let [init_arg] = args
         && is_inside_always_const_context(cx.tcx, expr.hir_id)
-        && is_type_diagnostic_item(cx, cx.typeck_results().node_type(ty.hir_id), sym::NonZero)
+        && is_type_lang_item(cx, cx.typeck_results().node_type(ty.hir_id), LangItem::NonZero)
         && msrv.meets(cx, msrvs::CONST_UNWRAP)
     {
         let mut app = Applicability::MachineApplicable;
diff --git a/src/tools/clippy/clippy_lints/src/non_zero_suggestions.rs b/src/tools/clippy/clippy_lints/src/non_zero_suggestions.rs
@@ -3,7 +3,7 @@ use clippy_utils::source::snippet;
 use clippy_utils::sym;
 use rustc_ast::ast::BinOpKind;
 use rustc_errors::Applicability;
-use rustc_hir::{Expr, ExprKind};
+use rustc_hir::{Expr, ExprKind, LangItem};
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::{self, Ty};
 use rustc_session::declare_lint_pass;
@@ -81,7 +81,7 @@ fn check_non_zero_conversion(cx: &LateContext<'_>, expr: &Expr<'_>, applicabilit
         // Check if the receiver type is a NonZero type
         if let ty::Adt(adt_def, _) = receiver_ty.kind()
             && adt_def.is_struct()
-            && cx.tcx.get_diagnostic_name(adt_def.did()) == Some(sym::NonZero)
+            && cx.tcx.is_lang_item(adt_def.did(), LangItem::NonZero)
             && let Some(target_non_zero_type) = get_target_non_zero_type(target_ty)
         {
             let arg_snippet = get_arg_snippet(cx, arg, rcv_path);
diff --git a/src/tools/clippy/clippy_lints/src/operators/arithmetic_side_effects.rs b/src/tools/clippy/clippy_lints/src/operators/arithmetic_side_effects.rs
@@ -5,6 +5,7 @@ use clippy_utils::diagnostics::span_lint;
 use clippy_utils::ty::is_type_diagnostic_item;
 use clippy_utils::{expr_or_init, is_from_proc_macro, is_lint_allowed, peel_hir_expr_refs, peel_hir_expr_unary};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_hir::LangItem;
 use rustc_lint::{LateContext, LateLintPass};
 use rustc_middle::ty::{self, Ty};
 use rustc_session::impl_lint_pass;
@@ -102,7 +103,7 @@ impl ArithmeticSideEffects {
 
             let ty::Adt(adt, substs) = ty.kind() else { return false };
 
-            if !tcx.is_diagnostic_item(sym::NonZero, adt.did()) {
+            if !tcx.is_lang_item(adt.did(), LangItem::NonZero) {
                 return false;
             }
 
diff --git a/src/tools/clippy/clippy_lints/src/operators/integer_division.rs b/src/tools/clippy/clippy_lints/src/operators/integer_division.rs
@@ -1,8 +1,7 @@
 use clippy_utils::diagnostics::span_lint_and_then;
-use clippy_utils::ty::is_type_diagnostic_item;
-use rustc_hir as hir;
+use clippy_utils::ty::is_type_lang_item;
+use rustc_hir::{self as hir, LangItem};
 use rustc_lint::LateContext;
-use rustc_span::symbol::sym;
 
 use super::INTEGER_DIVISION;
 
@@ -16,7 +15,7 @@ pub(crate) fn check<'tcx>(
     if op == hir::BinOpKind::Div
         && cx.typeck_results().expr_ty(left).is_integral()
         && let right_ty = cx.typeck_results().expr_ty(right)
-        && (right_ty.is_integral() || is_type_diagnostic_item(cx, right_ty, sym::NonZero))
+        && (right_ty.is_integral() || is_type_lang_item(cx, right_ty, LangItem::NonZero))
     {
         #[expect(clippy::collapsible_span_lint_calls, reason = "rust-clippy#7797")]
         span_lint_and_then(cx, INTEGER_DIVISION, expr.span, "integer division", |diag| {
diff --git a/src/tools/clippy/clippy_lints/src/transmute/transmute_int_to_non_zero.rs b/src/tools/clippy/clippy_lints/src/transmute/transmute_int_to_non_zero.rs
@@ -2,7 +2,7 @@ use super::TRANSMUTE_INT_TO_NON_ZERO;
 use clippy_utils::diagnostics::span_lint_and_then;
 use clippy_utils::sugg;
 use rustc_errors::Applicability;
-use rustc_hir::Expr;
+use rustc_hir::{Expr, LangItem};
 use rustc_lint::LateContext;
 use rustc_middle::ty::{self, Ty};
 use rustc_span::symbol::sym;
@@ -22,7 +22,7 @@ pub(super) fn check<'tcx>(
         return false;
     };
 
-    if !tcx.is_diagnostic_item(sym::NonZero, adt.did()) {
+    if !tcx.is_lang_item(adt.did(), LangItem::NonZero) {
         return false;
     }
 
diff --git a/tests/ui/mismatched_types/non_zero_assigned_lit.rs b/tests/ui/mismatched_types/non_zero_assigned_lit.rs
@@ -0,0 +1,8 @@
+//@ check-pass
+
+#![allow(overflowing_literals)]
+
+fn main() {
+    let x: std::num::NonZero<i8> = -128;
+    assert_eq!(x.get(), -128_i8);
+}
diff --git a/tests/ui/mismatched_types/non_zero_assigned_oflo_lit.rs b/tests/ui/mismatched_types/non_zero_assigned_oflo_lit.rs
@@ -0,0 +1,15 @@
+//! Ensure overflowing literals are not allowed for
+//! layout constrained types like `NonZero`, as that makes
+//! it harder to perform the layout checks. Instead
+//! we hard error if such literals are out of range.
+
+#![allow(overflowing_literals)]
+
+fn main() {
+    let _: std::num::NonZero<u8> = 256;
+    //~^ ERROR literal out of range
+
+    let _: std::num::NonZero<i8> = -128;
+    let _: std::num::NonZero<i8> = -129;
+    //~^ ERROR literal out of range
+}
diff --git a/tests/ui/mismatched_types/non_zero_assigned_oflo_lit.stderr b/tests/ui/mismatched_types/non_zero_assigned_oflo_lit.stderr
@@ -0,0 +1,18 @@
+error: literal out of range for `u8`
+  --> $DIR/non_zero_assigned_oflo_lit.rs:9:36
+   |
+LL |     let _: std::num::NonZero<u8> = 256;
+   |                                    ^^^
+   |
+   = note: the literal `256` does not fit into the type `u8` whose range is `0..=255`
+
+error: literal out of range for `i8`
+  --> $DIR/non_zero_assigned_oflo_lit.rs:13:36
+   |
+LL |     let _: std::num::NonZero<i8> = -129;
+   |                                    ^^^^
+   |
+   = note: the literal `-129` does not fit into the type `i8` whose range is `-128..=127`
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/mismatched_types/non_zero_assigned_something.rs b/tests/ui/mismatched_types/non_zero_assigned_something.rs
diff --git a/tests/ui/mismatched_types/non_zero_assigned_something.stderr b/tests/ui/mismatched_types/non_zero_assigned_something.stderr

Original file line number	Diff line number	Diff line change
`@@ -2487,7 +2487,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {`
`2487`	`2487`	`_ => return false,`
`2488`	`2488`	`};`
`2489`	`2489`
`2490`		`- if !self.tcx.is_diagnostic_item(sym::NonZero, adt.did()) {`
	`2490`	`+ if !self.tcx.is_lang_item(adt.did(), LangItem::NonZero) {`
`2491`	`2491`	`return false;`
`2492`	`2492`	`}`
`2493`	`2493`