Auto merge of #123207 - Urgau:improve_ambi_non_null, r=Nadrieril

Add support for `NonNull`s in the `ambiguous_wide_ptr_comparisions` lint

This PR add support for `NonNull` pointers in the `ambiguous_wide_ptr_comparisions` lint.

Fixes #121264
r? `@Nadrieril` (since you just reviewed #121268, feel free to reassign)

Author: bors

compiler/rustc_data_structures/src/tagged_ptr/copy.rs

@@ -243,6 +243,7 @@ where
     T: Tag,
 {
     #[inline]
+    #[allow(ambiguous_wide_pointer_comparisons)]
     fn eq(&self, other: &Self) -> bool {
         self.packed == other.packed
     }

compiler/rustc_lint/src/lints.rs

@@ -1632,11 +1632,13 @@ pub struct AmbiguousWidePointerComparisonsAddrMetadataSuggestion<'a> {
     pub ne: &'a str,
     pub deref_left: &'a str,
     pub deref_right: &'a str,
+    pub l_modifiers: &'a str,
+    pub r_modifiers: &'a str,
     #[suggestion_part(code = "{ne}std::ptr::eq({deref_left}")]
     pub left: Span,
-    #[suggestion_part(code = ", {deref_right}")]
+    #[suggestion_part(code = "{l_modifiers}, {deref_right}")]
     pub middle: Span,
-    #[suggestion_part(code = ")")]
+    #[suggestion_part(code = "{r_modifiers})")]
     pub right: Span,
 }
 
@@ -1652,11 +1654,13 @@ pub enum AmbiguousWidePointerComparisonsAddrSuggestion<'a> {
         ne: &'a str,
         deref_left: &'a str,
         deref_right: &'a str,
+        l_modifiers: &'a str,
+        r_modifiers: &'a str,
         #[suggestion_part(code = "{ne}std::ptr::addr_eq({deref_left}")]
         left: Span,
-        #[suggestion_part(code = ", {deref_right}")]
+        #[suggestion_part(code = "{l_modifiers}, {deref_right}")]
         middle: Span,
-        #[suggestion_part(code = ")")]
+        #[suggestion_part(code = "{r_modifiers})")]
         right: Span,
     },
     #[multipart_suggestion(
@@ -1670,13 +1674,15 @@ pub enum AmbiguousWidePointerComparisonsAddrSuggestion<'a> {
         deref_right: &'a str,
         paren_left: &'a str,
         paren_right: &'a str,
+        l_modifiers: &'a str,
+        r_modifiers: &'a str,
         #[suggestion_part(code = "({deref_left}")]
         left_before: Option<Span>,
-        #[suggestion_part(code = "{paren_left}.cast::<()>()")]
+        #[suggestion_part(code = "{l_modifiers}{paren_left}.cast::<()>()")]
         left_after: Span,
         #[suggestion_part(code = "({deref_right}")]
         right_before: Option<Span>,
-        #[suggestion_part(code = "{paren_right}.cast::<()>()")]
+        #[suggestion_part(code = "{r_modifiers}{paren_right}.cast::<()>()")]
         right_after: Span,
     },
 }

compiler/rustc_lint/src/types.rs

@@ -670,19 +670,32 @@ fn lint_wide_pointer<'tcx>(
     l: &'tcx hir::Expr<'tcx>,
     r: &'tcx hir::Expr<'tcx>,
 ) {
-    let ptr_unsized = |mut ty: Ty<'tcx>| -> Option<(usize, bool)> {
+    let ptr_unsized = |mut ty: Ty<'tcx>| -> Option<(
+        /* number of refs */ usize,
+        /* modifiers */ String,
+        /* is dyn */ bool,
+    )> {
         let mut refs = 0;
         // here we remove any "implicit" references and count the number
         // of them to correctly suggest the right number of deref
         while let ty::Ref(_, inner_ty, _) = ty.kind() {
             ty = *inner_ty;
             refs += 1;
         }
-        match ty.kind() {
-            ty::RawPtr(ty, _) => (!ty.is_sized(cx.tcx, cx.param_env))
-                .then(|| (refs, matches!(ty.kind(), ty::Dynamic(_, _, ty::Dyn)))),
-            _ => None,
-        }
+
+        // get the inner type of a pointer (or akin)
+        let mut modifiers = String::new();
+        ty = match ty.kind() {
+            ty::RawPtr(ty, _) => *ty,
+            ty::Adt(def, args) if cx.tcx.is_diagnostic_item(sym::NonNull, def.did()) => {
+                modifiers.push_str(".as_ptr()");
+                args.type_at(0)
+            }
+            _ => return None,
+        };
+
+        (!ty.is_sized(cx.tcx, cx.param_env))
+            .then(|| (refs, modifiers, matches!(ty.kind(), ty::Dynamic(_, _, ty::Dyn))))
     };
 
     // the left and right operands can have references, remove any explicit references
@@ -696,10 +709,10 @@ fn lint_wide_pointer<'tcx>(
         return;
     };
 
-    let Some((l_ty_refs, l_inner_ty_is_dyn)) = ptr_unsized(l_ty) else {
+    let Some((l_ty_refs, l_modifiers, l_inner_ty_is_dyn)) = ptr_unsized(l_ty) else {
         return;
     };
-    let Some((r_ty_refs, r_inner_ty_is_dyn)) = ptr_unsized(r_ty) else {
+    let Some((r_ty_refs, r_modifiers, r_inner_ty_is_dyn)) = ptr_unsized(r_ty) else {
         return;
     };
 
@@ -724,6 +737,9 @@ fn lint_wide_pointer<'tcx>(
     let deref_left = &*"*".repeat(l_ty_refs);
     let deref_right = &*"*".repeat(r_ty_refs);
 
+    let l_modifiers = &*l_modifiers;
+    let r_modifiers = &*r_modifiers;
+
     cx.emit_span_lint(
         AMBIGUOUS_WIDE_POINTER_COMPARISONS,
         e.span,
@@ -733,6 +749,8 @@ fn lint_wide_pointer<'tcx>(
                     ne,
                     deref_left,
                     deref_right,
+                    l_modifiers,
+                    r_modifiers,
                     left,
                     middle,
                     right,
@@ -743,6 +761,8 @@ fn lint_wide_pointer<'tcx>(
                     ne,
                     deref_left,
                     deref_right,
+                    l_modifiers,
+                    r_modifiers,
                     left,
                     middle,
                     right,
@@ -751,6 +771,8 @@ fn lint_wide_pointer<'tcx>(
                 AmbiguousWidePointerComparisonsAddrSuggestion::Cast {
                     deref_left,
                     deref_right,
+                    l_modifiers,
+                    r_modifiers,
                     paren_left: if l_ty_refs != 0 { ")" } else { "" },
                     paren_right: if r_ty_refs != 0 { ")" } else { "" },
                     left_before: (l_ty_refs != 0).then_some(l_span.shrink_to_lo()),

tests/ui/lint/wide_pointer_comparisons.rs

@@ -3,6 +3,7 @@
 use std::rc::Rc;
 use std::sync::Arc;
 use std::cmp::PartialEq;
+use std::ptr::NonNull;
 
 struct A;
 struct B;
@@ -50,6 +51,17 @@ fn main() {
     let _ = a.gt(&b);
     //~^ WARN ambiguous wide pointer comparison
 
+    {
+        let a = NonNull::<dyn T>::new(a as *mut _).unwrap();
+        let b = NonNull::<dyn T>::new(b as *mut _).unwrap();
+        let _ = a == b;
+        //~^ WARN ambiguous wide pointer comparison
+        let _ = a >= b;
+        //~^ WARN ambiguous wide pointer comparison
+        let _ = &a == &b;
+        //~^ WARN ambiguous wide pointer comparison
+    }
+
     {
         // &*const ?Sized
         let a = &a;