diff --git a/compiler/rustc_ast_ir/src/lib.rs b/compiler/rustc_ast_ir/src/lib.rs
index ff7a155204716..9ff2e32f06b0f 100644
--- a/compiler/rustc_ast_ir/src/lib.rs
+++ b/compiler/rustc_ast_ir/src/lib.rs
@@ -51,6 +51,14 @@ impl Mutability {
}
}
+ /// Returns `"const"` or `"mut"` depending on the mutability.
+ pub fn ptr_str(self) -> &'static str {
+ match self {
+ Mutability::Not => "const",
+ Mutability::Mut => "mut",
+ }
+ }
+
/// Returns `""` (empty string) or `"mutably "` depending on the mutability.
pub fn mutably_str(self) -> &'static str {
match self {
diff --git a/compiler/rustc_hir_typeck/src/method/suggest.rs b/compiler/rustc_hir_typeck/src/method/suggest.rs
index a199f57aad99f..754866c85c4a0 100644
--- a/compiler/rustc_hir_typeck/src/method/suggest.rs
+++ b/compiler/rustc_hir_typeck/src/method/suggest.rs
@@ -529,16 +529,44 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
Applicability::MachineApplicable,
);
}
- if let ty::RawPtr(_, _) = &rcvr_ty.kind() {
- err.note(
- "try using `<*const T>::as_ref()` to get a reference to the \
- type behind the pointer: https://doc.rust-lang.org/std/\
- primitive.pointer.html#method.as_ref",
- );
- err.note(
- "using `<*const T>::as_ref()` on a pointer which is unaligned or points \
- to invalid or uninitialized memory is undefined behavior",
+
+ // on pointers, check if the method would exist on a reference
+ if let SelfSource::MethodCall(rcvr_expr) = source
+ && let ty::RawPtr(ty, ptr_mutbl) = *rcvr_ty.kind()
+ && let Ok(pick) = self.lookup_probe_for_diagnostic(
+ item_name,
+ Ty::new_ref(tcx, ty::Region::new_error_misc(tcx), ty, ptr_mutbl),
+ self.tcx.hir().expect_expr(self.tcx.parent_hir_id(rcvr_expr.hir_id)),
+ ProbeScope::TraitsInScope,
+ None,
+ )
+ && let ty::Ref(_, _, sugg_mutbl) = *pick.self_ty.kind()
+ && (sugg_mutbl.is_not() || ptr_mutbl.is_mut())
+ {
+ let (method, method_anchor) = match sugg_mutbl {
+ Mutability::Not => {
+ let method_anchor = match ptr_mutbl {
+ Mutability::Not => "as_ref",
+ Mutability::Mut => "as_ref-1",
+ };
+ ("as_ref", method_anchor)
+ }
+ Mutability::Mut => ("as_mut", "as_mut"),
+ };
+ err.span_note(
+ tcx.def_span(pick.item.def_id),
+ format!("the method `{item_name}` exists on the type `{ty}`", ty = pick.self_ty),
);
+ let mut_str = ptr_mutbl.ptr_str();
+ err.note(format!(
+ "you might want to use the unsafe method `<*{mut_str} T>::{method}` to get \
+ an optional reference to the value behind the pointer"
+ ));
+ err.note(format!(
+ "read the documentation for `<*{mut_str} T>::{method}` and ensure you satisfy its \
+ safety preconditions before calling it to avoid undefined behavior: \
+ https://doc.rust-lang.org/std/primitive.pointer.html#method.{method_anchor}"
+ ));
}
let mut ty_span = match rcvr_ty.kind() {
diff --git a/compiler/rustc_middle/src/mir/pretty.rs b/compiler/rustc_middle/src/mir/pretty.rs
index 41df2e3b5875a..15bd5c089652c 100644
--- a/compiler/rustc_middle/src/mir/pretty.rs
+++ b/compiler/rustc_middle/src/mir/pretty.rs
@@ -978,12 +978,7 @@ impl<'tcx> Debug for Rvalue<'tcx> {
CopyForDeref(ref place) => write!(fmt, "deref_copy {place:#?}"),
AddressOf(mutability, ref place) => {
- let kind_str = match mutability {
- Mutability::Mut => "mut",
- Mutability::Not => "const",
- };
-
- write!(fmt, "&raw {kind_str} {place:?}")
+ write!(fmt, "&raw {mut_str} {place:?}", mut_str = mutability.ptr_str())
}
Aggregate(ref kind, ref places) => {
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index 20ebd87c3d4ca..0bd009cd51da1 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -671,13 +671,7 @@ pub trait PrettyPrinter<'tcx>: Printer<'tcx> + fmt::Write {
p!("(", print(ty), ") is ", write("{pat:?}"))
}
ty::RawPtr(ty, mutbl) => {
- p!(write(
- "*{} ",
- match mutbl {
- hir::Mutability::Mut => "mut",
- hir::Mutability::Not => "const",
- }
- ));
+ p!(write("*{} ", mutbl.ptr_str()));
p!(print(ty))
}
ty::Ref(r, ty, mutbl) => {
diff --git a/compiler/rustc_type_ir/src/ty_kind.rs b/compiler/rustc_type_ir/src/ty_kind.rs
index 8813955f2af05..56ae7ad9f741a 100644
--- a/compiler/rustc_type_ir/src/ty_kind.rs
+++ b/compiler/rustc_type_ir/src/ty_kind.rs
@@ -373,17 +373,8 @@ impl<I: Interner> DebugWithInfcx<I> for TyKind<I> {
Array(t, c) => write!(f, "[{:?}; {:?}]", &this.wrap(t), &this.wrap(c)),
Pat(t, p) => write!(f, "pattern_type!({:?} is {:?})", &this.wrap(t), &this.wrap(p)),
Slice(t) => write!(f, "[{:?}]", &this.wrap(t)),
- RawPtr(ty, mutbl) => {
- match mutbl {
- Mutability::Mut => write!(f, "*mut "),
- Mutability::Not => write!(f, "*const "),
- }?;
- write!(f, "{:?}", &this.wrap(ty))
- }
- Ref(r, t, m) => match m {
- Mutability::Mut => write!(f, "&{:?} mut {:?}", &this.wrap(r), &this.wrap(t)),
- Mutability::Not => write!(f, "&{:?} {:?}", &this.wrap(r), &this.wrap(t)),
- },
+ RawPtr(ty, mutbl) => write!(f, "*{} {:?}", mutbl.ptr_str(), this.wrap(ty)),
+ Ref(r, t, m) => write!(f, "&{:?} {}{:?}", this.wrap(r), m.prefix_str(), this.wrap(t)),
FnDef(d, s) => f.debug_tuple("FnDef").field(d).field(&this.wrap(s)).finish(),
FnPtr(s) => write!(f, "{:?}", &this.wrap(s)),
Dynamic(p, r, repr) => match repr {
diff --git a/src/tools/tidy/src/issues.txt b/src/tools/tidy/src/issues.txt
index e14932ad99d85..211dc347b0fdd 100644
--- a/src/tools/tidy/src/issues.txt
+++ b/src/tools/tidy/src/issues.txt
@@ -1791,7 +1791,6 @@ ui/issues/issue-2150.rs
ui/issues/issue-2151.rs
ui/issues/issue-21546.rs
ui/issues/issue-21554.rs
-ui/issues/issue-21596.rs
ui/issues/issue-21600.rs
ui/issues/issue-21622.rs
ui/issues/issue-21634.rs
diff --git a/src/tools/tidy/src/ui_tests.rs b/src/tools/tidy/src/ui_tests.rs
index 78de8c0537dcc..7136bc4d8f21a 100644
--- a/src/tools/tidy/src/ui_tests.rs
+++ b/src/tools/tidy/src/ui_tests.rs
@@ -17,7 +17,7 @@ use std::path::{Path, PathBuf};
const ENTRY_LIMIT: usize = 900;
// FIXME: The following limits should be reduced eventually.
-const ISSUES_ENTRY_LIMIT: usize = 1722;
+const ISSUES_ENTRY_LIMIT: usize = 1720;
const ROOT_ENTRY_LIMIT: usize = 859;
const EXPECTED_TEST_FILE_EXTENSIONS: &[&str] = &[
diff --git a/tests/ui/issues/issue-21596.rs b/tests/ui/issues/issue-21596.rs
deleted file mode 100644
index 79f6c91d9ac97..0000000000000
--- a/tests/ui/issues/issue-21596.rs
+++ /dev/null
@@ -1,5 +0,0 @@
-fn main() {
- let x = 8u8;
- let z: *const u8 = &x;
- println!("{}", z.to_string()); //~ ERROR E0599
-}
diff --git a/tests/ui/issues/issue-21596.stderr b/tests/ui/issues/issue-21596.stderr
deleted file mode 100644
index 8a7fca5f43647..0000000000000
--- a/tests/ui/issues/issue-21596.stderr
+++ /dev/null
@@ -1,15 +0,0 @@
-error[E0599]: `*const u8` doesn't implement `std::fmt::Display`
- --> $DIR/issue-21596.rs:4:22
- |
-LL | println!("{}", z.to_string());
- | ^^^^^^^^^ `*const u8` cannot be formatted with the default formatter
- |
- = note: try using `<*const T>::as_ref()` to get a reference to the type behind the pointer: https://doc.rust-lang.org/std/primitive.pointer.html#method.as_ref
- = note: using `<*const T>::as_ref()` on a pointer which is unaligned or points to invalid or uninitialized memory is undefined behavior
- = note: the following trait bounds were not satisfied:
- `*const u8: std::fmt::Display`
- which is required by `*const u8: ToString`
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0599`.
diff --git a/tests/ui/methods/suggest-convert-ptr-to-ref.rs b/tests/ui/methods/suggest-convert-ptr-to-ref.rs
new file mode 100644
index 0000000000000..ccce3c65470df
--- /dev/null
+++ b/tests/ui/methods/suggest-convert-ptr-to-ref.rs
@@ -0,0 +1,17 @@
+fn main() {
+ let mut x = 8u8;
+ let z: *const u8 = &x;
+ // issue #21596
+ println!("{}", z.to_string()); //~ ERROR E0599
+
+ let t: *mut u8 = &mut x;
+ println!("{}", t.to_string()); //~ ERROR E0599
+ t.make_ascii_lowercase(); //~ ERROR E0599
+
+ // suggest `as_mut` simply because the name is similar
+ let _ = t.as_mut_ref(); //~ ERROR E0599
+ let _ = t.as_ref_mut(); //~ ERROR E0599
+
+ // no ptr-to-ref suggestion
+ z.make_ascii_lowercase(); //~ ERROR E0599
+}
diff --git a/tests/ui/methods/suggest-convert-ptr-to-ref.stderr b/tests/ui/methods/suggest-convert-ptr-to-ref.stderr
new file mode 100644
index 0000000000000..69b20d57be829
--- /dev/null
+++ b/tests/ui/methods/suggest-convert-ptr-to-ref.stderr
@@ -0,0 +1,70 @@
+error[E0599]: `*const u8` doesn't implement `std::fmt::Display`
+ --> $DIR/suggest-convert-ptr-to-ref.rs:5:22
+ |
+LL | println!("{}", z.to_string());
+ | ^^^^^^^^^ `*const u8` cannot be formatted with the default formatter
+ |
+note: the method `to_string` exists on the type `&u8`
+ --> $SRC_DIR/alloc/src/string.rs:LL:COL
+ = note: you might want to use the unsafe method `<*const T>::as_ref` to get an optional reference to the value behind the pointer
+ = note: read the documentation for `<*const T>::as_ref` and ensure you satisfy its safety preconditions before calling it to avoid undefined behavior: https://doc.rust-lang.org/std/primitive.pointer.html#method.as_ref
+ = note: the following trait bounds were not satisfied:
+ `*const u8: std::fmt::Display`
+ which is required by `*const u8: ToString`
+
+error[E0599]: `*mut u8` doesn't implement `std::fmt::Display`
+ --> $DIR/suggest-convert-ptr-to-ref.rs:8:22
+ |
+LL | println!("{}", t.to_string());
+ | ^^^^^^^^^ `*mut u8` cannot be formatted with the default formatter
+ |
+note: the method `to_string` exists on the type `&&mut u8`
+ --> $SRC_DIR/alloc/src/string.rs:LL:COL
+ = note: you might want to use the unsafe method `<*mut T>::as_ref` to get an optional reference to the value behind the pointer
+ = note: read the documentation for `<*mut T>::as_ref` and ensure you satisfy its safety preconditions before calling it to avoid undefined behavior: https://doc.rust-lang.org/std/primitive.pointer.html#method.as_ref-1
+ = note: the following trait bounds were not satisfied:
+ `*mut u8: std::fmt::Display`
+ which is required by `*mut u8: ToString`
+
+error[E0599]: no method named `make_ascii_lowercase` found for raw pointer `*mut u8` in the current scope
+ --> $DIR/suggest-convert-ptr-to-ref.rs:9:7
+ |
+LL | t.make_ascii_lowercase();
+ | ^^^^^^^^^^^^^^^^^^^^ method not found in `*mut u8`
+ |
+note: the method `make_ascii_lowercase` exists on the type `&mut u8`
+ --> $SRC_DIR/core/src/num/mod.rs:LL:COL
+ = note: you might want to use the unsafe method `<*mut T>::as_mut` to get an optional reference to the value behind the pointer
+ = note: read the documentation for `<*mut T>::as_mut` and ensure you satisfy its safety preconditions before calling it to avoid undefined behavior: https://doc.rust-lang.org/std/primitive.pointer.html#method.as_mut
+
+error[E0599]: no method named `as_mut_ref` found for raw pointer `*mut u8` in the current scope
+ --> $DIR/suggest-convert-ptr-to-ref.rs:12:15
+ |
+LL | let _ = t.as_mut_ref();
+ | ^^^^^^^^^^
+ |
+help: there is a method `as_mut` with a similar name
+ |
+LL | let _ = t.as_mut();
+ | ~~~~~~
+
+error[E0599]: no method named `as_ref_mut` found for raw pointer `*mut u8` in the current scope
+ --> $DIR/suggest-convert-ptr-to-ref.rs:13:15
+ |
+LL | let _ = t.as_ref_mut();
+ | ^^^^^^^^^^
+ |
+help: there is a method `as_mut` with a similar name
+ |
+LL | let _ = t.as_mut();
+ | ~~~~~~
+
+error[E0599]: no method named `make_ascii_lowercase` found for raw pointer `*const u8` in the current scope
+ --> $DIR/suggest-convert-ptr-to-ref.rs:16:7
+ |
+LL | z.make_ascii_lowercase();
+ | ^^^^^^^^^^^^^^^^^^^^ method not found in `*const u8`
+
+error: aborting due to 6 previous errors
+
+For more information about this error, try `rustc --explain E0599`.