diff --git a/compiler/rustc_driver_impl/src/lib.rs b/compiler/rustc_driver_impl/src/lib.rs index f8dda23ef9cf6..2f1c78197275d 100644 --- a/compiler/rustc_driver_impl/src/lib.rs +++ b/compiler/rustc_driver_impl/src/lib.rs @@ -771,9 +771,7 @@ fn print_crate_info( use rustc_target::spec::SplitDebuginfo::{Off, Packed, Unpacked}; for split in &[Off, Packed, Unpacked] { - let stable = sess.target.options.supported_split_debuginfo.contains(split); - let unstable_ok = sess.unstable_options(); - if stable || unstable_ok { + if sess.target.options.supported_split_debuginfo.contains(split) { safe_println!("{split}"); } } diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs index c7b9fc9a697f4..8b5c1791fc139 100644 --- a/compiler/rustc_hir_analysis/src/collect.rs +++ b/compiler/rustc_hir_analysis/src/collect.rs @@ -666,17 +666,15 @@ fn convert_trait_item(tcx: TyCtxt<'_>, trait_item_id: hir::TraitItemId) { tcx.ensure().fn_sig(def_id); } - hir::TraitItemKind::Const(.., Some(_)) => { + hir::TraitItemKind::Const(ty, body_id) => { tcx.ensure().type_of(def_id); - } - - hir::TraitItemKind::Const(hir_ty, _) => { - tcx.ensure().type_of(def_id); - // Account for `const C: _;`. - let mut visitor = HirPlaceholderCollector::default(); - visitor.visit_trait_item(trait_item); - if !tcx.sess.diagnostic().has_stashed_diagnostic(hir_ty.span, StashKey::ItemNoType) { - placeholder_type_error(tcx, None, visitor.0, false, None, "constant"); + if !tcx.sess.diagnostic().has_stashed_diagnostic(ty.span, StashKey::ItemNoType) + && !(is_suggestable_infer_ty(ty) && body_id.is_some()) + { + // Account for `const C: _;`. + let mut visitor = HirPlaceholderCollector::default(); + visitor.visit_trait_item(trait_item); + placeholder_type_error(tcx, None, visitor.0, false, None, "associated constant"); } } @@ -721,7 +719,14 @@ fn convert_impl_item(tcx: TyCtxt<'_>, impl_item_id: hir::ImplItemId) { placeholder_type_error(tcx, None, visitor.0, false, None, "associated type"); } - hir::ImplItemKind::Const(..) => {} + hir::ImplItemKind::Const(ty, _) => { + // Account for `const T: _ = ..;` + if !is_suggestable_infer_ty(ty) { + let mut visitor = HirPlaceholderCollector::default(); + visitor.visit_impl_item(impl_item); + placeholder_type_error(tcx, None, visitor.0, false, None, "associated constant"); + } + } } } diff --git a/compiler/rustc_hir_analysis/src/collect/type_of.rs b/compiler/rustc_hir_analysis/src/collect/type_of.rs index c2b837fcfa670..318d0d0c22397 100644 --- a/compiler/rustc_hir_analysis/src/collect/type_of.rs +++ b/compiler/rustc_hir_analysis/src/collect/type_of.rs @@ -341,7 +341,12 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: LocalDefId) -> ty::EarlyBinder, def_id: LocalDefId) -> ty::EarlyBinder { if is_suggestable_infer_ty(ty) { - infer_placeholder_type(tcx, def_id, body_id, ty.span, item.ident, "constant") + infer_placeholder_type( + tcx, + def_id, + body_id, + ty.span, + item.ident, + "associated constant", + ) } else { icx.to_ty(ty) } diff --git a/library/alloc/src/string.rs b/library/alloc/src/string.rs index 59e3f887b5232..1c6815fa94110 100644 --- a/library/alloc/src/string.rs +++ b/library/alloc/src/string.rs @@ -1853,26 +1853,27 @@ impl String { /// Consumes and leaks the `String`, returning a mutable reference to the contents, /// `&'a mut str`. /// - /// This is mainly useful for data that lives for the remainder of - /// the program's life. Dropping the returned reference will cause a memory - /// leak. + /// The caller has free choice over the returned lifetime, including `'static`. Indeed, + /// this function is ideally used for data that lives for the remainder of the program's life, + /// as dropping the returned reference will cause a memory leak. /// /// It does not reallocate or shrink the `String`, /// so the leaked allocation may include unused capacity that is not part - /// of the returned slice. + /// of the returned slice. If you don't want that, call [`into_boxed_str`], + /// and then [`Box::leak`]. + /// + /// [`into_boxed_str`]: Self::into_boxed_str /// /// # Examples /// /// Simple usage: /// /// ``` - /// #![feature(string_leak)] - /// /// let x = String::from("bucket"); /// let static_ref: &'static mut str = x.leak(); /// assert_eq!(static_ref, "bucket"); /// ``` - #[unstable(feature = "string_leak", issue = "102929")] + #[stable(feature = "string_leak", since = "CURRENT_RUSTC_VERSION")] #[inline] pub fn leak<'a>(self) -> &'a mut str { let slice = self.vec.leak(); diff --git a/library/core/src/slice/mod.rs b/library/core/src/slice/mod.rs index c87af35fbc449..5d6e7dcfcee87 100644 --- a/library/core/src/slice/mod.rs +++ b/library/core/src/slice/mod.rs @@ -2995,7 +2995,7 @@ impl [T] { /// This reordering has the additional property that any value at position `i < index` will be /// less than or equal to any value at a position `j > index`. Additionally, this reordering is /// unstable (i.e. any number of equal elements may end up at position `index`), in-place - /// (i.e. does not allocate), and *O*(*n*) on average. The worst-case performance is *O*(*n* log *n*). + /// (i.e. does not allocate), and runs in *O*(*n*) time. /// This function is also known as "kth element" in other libraries. /// /// It returns a triplet of the following from the reordered slice: @@ -3045,9 +3045,8 @@ impl [T] { /// This reordering has the additional property that any value at position `i < index` will be /// less than or equal to any value at a position `j > index` using the comparator function. /// Additionally, this reordering is unstable (i.e. any number of equal elements may end up at - /// position `index`), in-place (i.e. does not allocate), and *O*(*n*) on average. - /// The worst-case performance is *O*(*n* log *n*). This function is also known as - /// "kth element" in other libraries. + /// position `index`), in-place (i.e. does not allocate), and runs in *O*(*n*) time. + /// This function is also known as "kth element" in other libraries. /// /// It returns a triplet of the following from /// the slice reordered according to the provided comparator function: the subslice prior to @@ -3101,8 +3100,7 @@ impl [T] { /// This reordering has the additional property that any value at position `i < index` will be /// less than or equal to any value at a position `j > index` using the key extraction function. /// Additionally, this reordering is unstable (i.e. any number of equal elements may end up at - /// position `index`), in-place (i.e. does not allocate), and *O*(*n*) on average. - /// The worst-case performance is *O*(*n* log *n*). + /// position `index`), in-place (i.e. does not allocate), and runs in *O*(*n*) time. /// This function is also known as "kth element" in other libraries. /// /// It returns a triplet of the following from diff --git a/library/std/src/collections/hash/set.rs b/library/std/src/collections/hash/set.rs index ac906e682d5f0..99620610d1c4e 100644 --- a/library/std/src/collections/hash/set.rs +++ b/library/std/src/collections/hash/set.rs @@ -868,7 +868,9 @@ where /// Returns whether the value was newly inserted. That is: /// /// - If the set did not previously contain this value, `true` is returned. - /// - If the set already contained this value, `false` is returned. + /// - If the set already contained this value, `false` is returned, + /// and the set is not modified: original value is not replaced, + /// and the value passed as argument is dropped. /// /// # Examples /// diff --git a/library/std/src/collections/hash/set/tests.rs b/library/std/src/collections/hash/set/tests.rs index 941a0450cc770..022ca68ffcfbb 100644 --- a/library/std/src/collections/hash/set/tests.rs +++ b/library/std/src/collections/hash/set/tests.rs @@ -3,6 +3,7 @@ use super::HashSet; use crate::panic::{catch_unwind, AssertUnwindSafe}; use crate::sync::atomic::{AtomicU32, Ordering}; +use crate::sync::Arc; #[test] fn test_zero_capacities() { @@ -502,3 +503,22 @@ fn const_with_hasher() { const X: HashSet<(), ()> = HashSet::with_hasher(()); assert_eq!(X.len(), 0); } + +#[test] +fn test_insert_does_not_overwrite_the_value() { + let first_value = Arc::new(17); + let second_value = Arc::new(17); + + let mut set = HashSet::new(); + let inserted = set.insert(first_value.clone()); + assert!(inserted); + + let inserted = set.insert(second_value); + assert!(!inserted); + + assert!( + Arc::ptr_eq(set.iter().next().unwrap(), &first_value), + "Insert must not overwrite the value, so the contained value pointer \ + must be the same as first value pointer we inserted" + ); +} diff --git a/library/std/src/ffi/os_str.rs b/library/std/src/ffi/os_str.rs index bb577acf769d4..fbdf7f5ecacc1 100644 --- a/library/std/src/ffi/os_str.rs +++ b/library/std/src/ffi/os_str.rs @@ -745,7 +745,7 @@ impl OsStr { without modifying the original"] #[inline] pub fn to_str(&self) -> Option<&str> { - self.inner.to_str() + self.inner.to_str().ok() } /// Converts an `OsStr` to a [Cow]<[str]>. @@ -1165,6 +1165,24 @@ impl<'a> From> for OsString { } } +#[stable(feature = "str_tryfrom_osstr_impl", since = "CURRENT_RUSTC_VERSION")] +impl<'a> TryFrom<&'a OsStr> for &'a str { + type Error = crate::str::Utf8Error; + + /// Tries to convert an `&OsStr` to a `&str`. + /// + /// ``` + /// use std::ffi::OsStr; + /// + /// let os_str = OsStr::new("foo"); + /// let as_str = <&str>::try_from(os_str).unwrap(); + /// assert_eq!(as_str, "foo"); + /// ``` + fn try_from(value: &'a OsStr) -> Result { + value.inner.to_str() + } +} + #[stable(feature = "box_default_extra", since = "1.17.0")] impl Default for Box { #[inline] diff --git a/library/std/src/sys/unix/os_str.rs b/library/std/src/sys/unix/os_str.rs index 142fcb9ed0b73..f7333fd5a1fed 100644 --- a/library/std/src/sys/unix/os_str.rs +++ b/library/std/src/sys/unix/os_str.rs @@ -207,8 +207,8 @@ impl Slice { unsafe { Slice::from_os_str_bytes_unchecked(s.as_bytes()) } } - pub fn to_str(&self) -> Option<&str> { - str::from_utf8(&self.inner).ok() + pub fn to_str(&self) -> Result<&str, crate::str::Utf8Error> { + str::from_utf8(&self.inner) } pub fn to_string_lossy(&self) -> Cow<'_, str> { diff --git a/library/std/src/sys/windows/os_str.rs b/library/std/src/sys/windows/os_str.rs index 611f0d040f0eb..16c4f55c6879a 100644 --- a/library/std/src/sys/windows/os_str.rs +++ b/library/std/src/sys/windows/os_str.rs @@ -166,7 +166,7 @@ impl Slice { unsafe { mem::transmute(Wtf8::from_str(s)) } } - pub fn to_str(&self) -> Option<&str> { + pub fn to_str(&self) -> Result<&str, crate::str::Utf8Error> { self.inner.as_str() } diff --git a/library/std/src/sys_common/wtf8.rs b/library/std/src/sys_common/wtf8.rs index 31bb0ad25a656..c9d3e13cf0c56 100644 --- a/library/std/src/sys_common/wtf8.rs +++ b/library/std/src/sys_common/wtf8.rs @@ -626,13 +626,8 @@ impl Wtf8 { /// /// This does not copy the data. #[inline] - pub fn as_str(&self) -> Option<&str> { - // Well-formed WTF-8 is also well-formed UTF-8 - // if and only if it contains no surrogate. - match self.next_surrogate(0) { - None => Some(unsafe { str::from_utf8_unchecked(&self.bytes) }), - Some(_) => None, - } + pub fn as_str(&self) -> Result<&str, str::Utf8Error> { + str::from_utf8(&self.bytes) } /// Creates an owned `Wtf8Buf` from a borrowed `Wtf8`. diff --git a/library/std/src/sys_common/wtf8/tests.rs b/library/std/src/sys_common/wtf8/tests.rs index 1a302d646941b..a07bbe6d7e425 100644 --- a/library/std/src/sys_common/wtf8/tests.rs +++ b/library/std/src/sys_common/wtf8/tests.rs @@ -521,11 +521,11 @@ fn wtf8_code_points() { #[test] fn wtf8_as_str() { - assert_eq!(Wtf8::from_str("").as_str(), Some("")); - assert_eq!(Wtf8::from_str("aé 💩").as_str(), Some("aé 💩")); + assert_eq!(Wtf8::from_str("").as_str(), Ok("")); + assert_eq!(Wtf8::from_str("aé 💩").as_str(), Ok("aé 💩")); let mut string = Wtf8Buf::new(); string.push(CodePoint::from_u32(0xD800).unwrap()); - assert_eq!(string.as_str(), None); + assert!(string.as_str().is_err()); } #[test] diff --git a/tests/ui/associated-consts/infer-placeholder-in-non-suggestable-pos.rs b/tests/ui/associated-consts/infer-placeholder-in-non-suggestable-pos.rs new file mode 100644 index 0000000000000..40896c32e1113 --- /dev/null +++ b/tests/ui/associated-consts/infer-placeholder-in-non-suggestable-pos.rs @@ -0,0 +1,10 @@ +trait Trait { + const ASSOC: i32; +} + +impl Trait for () { + const ASSOC: &dyn Fn(_) = 1i32; + //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated constants +} + +fn main() {} diff --git a/tests/ui/associated-consts/infer-placeholder-in-non-suggestable-pos.stderr b/tests/ui/associated-consts/infer-placeholder-in-non-suggestable-pos.stderr new file mode 100644 index 0000000000000..993a08faba990 --- /dev/null +++ b/tests/ui/associated-consts/infer-placeholder-in-non-suggestable-pos.stderr @@ -0,0 +1,9 @@ +error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants + --> $DIR/infer-placeholder-in-non-suggestable-pos.rs:6:26 + | +LL | const ASSOC: &dyn Fn(_) = 1i32; + | ^ not allowed in type signatures + +error: aborting due to previous error + +For more information about this error, try `rustc --explain E0121`. diff --git a/tests/ui/const-generics/generic_arg_infer/in-signature.rs b/tests/ui/const-generics/generic_arg_infer/in-signature.rs index 1f60b2242411d..cd852a269435e 100644 --- a/tests/ui/const-generics/generic_arg_infer/in-signature.rs +++ b/tests/ui/const-generics/generic_arg_infer/in-signature.rs @@ -33,15 +33,15 @@ static TY_STATIC_MIXED: Bar<_, _> = Bar::(0); //~^ ERROR the placeholder `_` is not allowed within types on item signatures for static variables trait ArrAssocConst { const ARR: [u8; _]; - //~^ ERROR the placeholder `_` is not allowed within types on item signatures for constants + //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated constants } trait TyAssocConst { const ARR: Bar; - //~^ ERROR the placeholder `_` is not allowed within types on item signatures for constants + //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated constants } trait TyAssocConstMixed { const ARR: Bar<_, _>; - //~^ ERROR the placeholder `_` is not allowed within types on item signatures for constants + //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated constants } trait AssocTy { diff --git a/tests/ui/const-generics/generic_arg_infer/in-signature.stderr b/tests/ui/const-generics/generic_arg_infer/in-signature.stderr index 52d1b29f93222..b32018a6a2d22 100644 --- a/tests/ui/const-generics/generic_arg_infer/in-signature.stderr +++ b/tests/ui/const-generics/generic_arg_infer/in-signature.stderr @@ -74,19 +74,19 @@ LL | static TY_STATIC_MIXED: Bar<_, _> = Bar::(0); | not allowed in type signatures | help: replace with the correct type: `Bar` -error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants +error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants --> $DIR/in-signature.rs:35:21 | LL | const ARR: [u8; _]; | ^ not allowed in type signatures -error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants +error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants --> $DIR/in-signature.rs:39:25 | LL | const ARR: Bar; | ^ not allowed in type signatures -error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants +error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants --> $DIR/in-signature.rs:43:20 | LL | const ARR: Bar<_, _>; diff --git a/tests/ui/typeck/type-placeholder-fn-in-const.rs b/tests/ui/typeck/type-placeholder-fn-in-const.rs index ab2e2d8c53aa3..bbb95a5798af5 100644 --- a/tests/ui/typeck/type-placeholder-fn-in-const.rs +++ b/tests/ui/typeck/type-placeholder-fn-in-const.rs @@ -3,12 +3,13 @@ struct MyStruct; trait Test { const TEST: fn() -> _; //~^ ERROR: the placeholder `_` is not allowed within types on item signatures for functions [E0121] - //~| ERROR: the placeholder `_` is not allowed within types on item signatures for constants [E0121] + //~| ERROR: the placeholder `_` is not allowed within types on item signatures for associated constants [E0121] } impl Test for MyStruct { const TEST: fn() -> _ = 42; //~^ ERROR: the placeholder `_` is not allowed within types on item signatures for functions [E0121] + //~| ERROR: the placeholder `_` is not allowed within types on item signatures for associated constants [E0121] } fn main() {} diff --git a/tests/ui/typeck/type-placeholder-fn-in-const.stderr b/tests/ui/typeck/type-placeholder-fn-in-const.stderr index e7b2e554a8d42..302359d2500c9 100644 --- a/tests/ui/typeck/type-placeholder-fn-in-const.stderr +++ b/tests/ui/typeck/type-placeholder-fn-in-const.stderr @@ -4,7 +4,7 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures LL | const TEST: fn() -> _; | ^ not allowed in type signatures -error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants +error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants --> $DIR/type-placeholder-fn-in-const.rs:4:25 | LL | const TEST: fn() -> _; @@ -16,6 +16,12 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures LL | const TEST: fn() -> _ = 42; | ^ not allowed in type signatures -error: aborting due to 3 previous errors +error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants + --> $DIR/type-placeholder-fn-in-const.rs:10:25 + | +LL | const TEST: fn() -> _ = 42; + | ^ not allowed in type signatures + +error: aborting due to 4 previous errors For more information about this error, try `rustc --explain E0121`. diff --git a/tests/ui/typeck/typeck_type_placeholder_item.rs b/tests/ui/typeck/typeck_type_placeholder_item.rs index 46aed0f603e87..4eba14f5a93fb 100644 --- a/tests/ui/typeck/typeck_type_placeholder_item.rs +++ b/tests/ui/typeck/typeck_type_placeholder_item.rs @@ -190,9 +190,9 @@ trait Qux { type B = _; //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated types const C: _; - //~^ ERROR the placeholder `_` is not allowed within types on item signatures for constants + //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated constants const D: _ = 42; - //~^ ERROR the placeholder `_` is not allowed within types on item signatures for constants + //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated constants // type E: _; // FIXME: make the parser propagate the existence of `B` type F: std::ops::Fn(_); //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated types @@ -203,10 +203,10 @@ impl Qux for Struct { type B = _; //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated types const C: _; - //~^ ERROR the placeholder `_` is not allowed within types on item signatures for constants + //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated constants //~| ERROR associated constant in `impl` without body const D: _ = 42; - //~^ ERROR the placeholder `_` is not allowed within types on item signatures for constants + //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated constants } fn map(_: fn() -> Option<&'static T>) -> Option { diff --git a/tests/ui/typeck/typeck_type_placeholder_item.stderr b/tests/ui/typeck/typeck_type_placeholder_item.stderr index bc02547c65eb8..0c5e7e3cecb19 100644 --- a/tests/ui/typeck/typeck_type_placeholder_item.stderr +++ b/tests/ui/typeck/typeck_type_placeholder_item.stderr @@ -525,13 +525,13 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures LL | type B = _; | ^ not allowed in type signatures -error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants +error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants --> $DIR/typeck_type_placeholder_item.rs:192:14 | LL | const C: _; | ^ not allowed in type signatures -error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants +error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants --> $DIR/typeck_type_placeholder_item.rs:194:14 | LL | const D: _ = 42; @@ -642,13 +642,13 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures LL | type B = _; | ^ not allowed in type signatures -error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants +error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants --> $DIR/typeck_type_placeholder_item.rs:205:14 | LL | const C: _; | ^ not allowed in type signatures -error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants +error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants --> $DIR/typeck_type_placeholder_item.rs:208:14 | LL | const D: _ = 42; diff --git a/tests/ui/typeck/typeck_type_placeholder_item_help.rs b/tests/ui/typeck/typeck_type_placeholder_item_help.rs index c459d8c3cdc17..914f8a2b28b34 100644 --- a/tests/ui/typeck/typeck_type_placeholder_item_help.rs +++ b/tests/ui/typeck/typeck_type_placeholder_item_help.rs @@ -16,14 +16,14 @@ const TEST4: fn() -> _ = 42; trait Test5 { const TEST5: _ = 42; - //~^ ERROR the placeholder `_` is not allowed within types on item signatures for constants + //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated constants } struct Test6; impl Test6 { const TEST6: _ = 13; - //~^ ERROR the placeholder `_` is not allowed within types on item signatures for constants + //~^ ERROR the placeholder `_` is not allowed within types on item signatures for associated constants } pub fn main() { diff --git a/tests/ui/typeck/typeck_type_placeholder_item_help.stderr b/tests/ui/typeck/typeck_type_placeholder_item_help.stderr index 07a5dbd93c743..ed6f4088019f7 100644 --- a/tests/ui/typeck/typeck_type_placeholder_item_help.stderr +++ b/tests/ui/typeck/typeck_type_placeholder_item_help.stderr @@ -37,7 +37,7 @@ error[E0121]: the placeholder `_` is not allowed within types on item signatures LL | const TEST4: fn() -> _ = 42; | ^ not allowed in type signatures -error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants +error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants --> $DIR/typeck_type_placeholder_item_help.rs:18:18 | LL | const TEST5: _ = 42; @@ -46,7 +46,7 @@ LL | const TEST5: _ = 42; | not allowed in type signatures | help: replace with the correct type: `i32` -error[E0121]: the placeholder `_` is not allowed within types on item signatures for constants +error[E0121]: the placeholder `_` is not allowed within types on item signatures for associated constants --> $DIR/typeck_type_placeholder_item_help.rs:25:18 | LL | const TEST6: _ = 13;