From 3dcb5a39622fe705647ea0764a355a10b6913832 Mon Sep 17 00:00:00 2001 From: Kornel Date: Sun, 25 Aug 2024 11:20:42 +0100 Subject: [PATCH] Add str.as_str() for easy dereferencing of Box --- .../rustc_hir_typeck/src/method/suggest.rs | 15 +---------- library/alloc/src/lib.rs | 1 + library/alloc/src/rc/tests.rs | 4 +++ library/core/src/str/mod.rs | 11 ++++++++ tests/ui/suggestions/remove-as_str.rs | 21 --------------- tests/ui/suggestions/remove-as_str.stderr | 27 ------------------- 6 files changed, 17 insertions(+), 62 deletions(-) delete mode 100644 tests/ui/suggestions/remove-as_str.rs delete mode 100644 tests/ui/suggestions/remove-as_str.stderr diff --git a/compiler/rustc_hir_typeck/src/method/suggest.rs b/compiler/rustc_hir_typeck/src/method/suggest.rs index deabf693af2f5..7964dc3381640 100644 --- a/compiler/rustc_hir_typeck/src/method/suggest.rs +++ b/compiler/rustc_hir_typeck/src/method/suggest.rs @@ -1721,20 +1721,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> { } } - if item_name.name == sym::as_str && rcvr_ty.peel_refs().is_str() { - let msg = "remove this method call"; - let mut fallback_span = true; - if let SelfSource::MethodCall(expr) = source { - let call_expr = self.tcx.hir().expect_expr(self.tcx.parent_hir_id(expr.hir_id)); - if let Some(span) = call_expr.span.trim_start(expr.span) { - err.span_suggestion(span, msg, "", Applicability::MachineApplicable); - fallback_span = false; - } - } - if fallback_span { - err.span_label(span, msg); - } - } else if let Some(similar_candidate) = similar_candidate { + if let Some(similar_candidate) = similar_candidate { // Don't emit a suggestion if we found an actual method // that had unsatisfied trait bounds if unsatisfied_predicates.is_empty() diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs index f0597f295b3f0..ff5ddd16e07e3 100644 --- a/library/alloc/src/lib.rs +++ b/library/alloc/src/lib.rs @@ -93,6 +93,7 @@ // tidy-alphabetical-start #![cfg_attr(not(no_global_oom_handling), feature(const_alloc_error))] #![cfg_attr(not(no_global_oom_handling), feature(const_btree_len))] +#![cfg_attr(test, feature(str_as_str))] #![feature(alloc_layout_extra)] #![feature(allocator_api)] #![feature(array_chunks)] diff --git a/library/alloc/src/rc/tests.rs b/library/alloc/src/rc/tests.rs index 84e8b325f71fc..333e1bde31c1e 100644 --- a/library/alloc/src/rc/tests.rs +++ b/library/alloc/src/rc/tests.rs @@ -448,7 +448,11 @@ fn test_from_box_str() { use std::string::String; let s = String::from("foo").into_boxed_str(); + assert_eq!((&&&s).as_str(), "foo"); + let r: Rc = Rc::from(s); + assert_eq!((&r).as_str(), "foo"); + assert_eq!(r.as_str(), "foo"); assert_eq!(&r[..], "foo"); } diff --git a/library/core/src/str/mod.rs b/library/core/src/str/mod.rs index 9373d807f44e3..5b20e681c2409 100644 --- a/library/core/src/str/mod.rs +++ b/library/core/src/str/mod.rs @@ -2737,6 +2737,17 @@ impl str { pub fn substr_range(&self, substr: &str) -> Option> { self.as_bytes().subslice_range(substr.as_bytes()) } + + /// Returns the same string as a string slice `&str`. + /// + /// This method is redundant when used directly on `&str`, but + /// it helps dereferencing other string-like types to string slices, + /// for example references to `Box` or `Arc`. + #[inline] + #[unstable(feature = "str_as_str", issue = "130366")] + pub fn as_str(&self) -> &str { + self + } } #[stable(feature = "rust1", since = "1.0.0")] diff --git a/tests/ui/suggestions/remove-as_str.rs b/tests/ui/suggestions/remove-as_str.rs deleted file mode 100644 index 289a784ba6af3..0000000000000 --- a/tests/ui/suggestions/remove-as_str.rs +++ /dev/null @@ -1,21 +0,0 @@ -fn foo1(s: &str) { - s.as_str(); - //~^ ERROR no method named `as_str` found -} - -fn foo2<'a>(s: &'a str) { - s.as_str(); - //~^ ERROR no method named `as_str` found -} - -fn foo3(s: &mut str) { - s.as_str(); - //~^ ERROR no method named `as_str` found -} - -fn foo4(s: &&str) { - s.as_str(); - //~^ ERROR no method named `as_str` found -} - -fn main() {} diff --git a/tests/ui/suggestions/remove-as_str.stderr b/tests/ui/suggestions/remove-as_str.stderr deleted file mode 100644 index 534c497780a95..0000000000000 --- a/tests/ui/suggestions/remove-as_str.stderr +++ /dev/null @@ -1,27 +0,0 @@ -error[E0599]: no method named `as_str` found for reference `&str` in the current scope - --> $DIR/remove-as_str.rs:2:7 - | -LL | s.as_str(); - | -^^^^^^-- help: remove this method call - -error[E0599]: no method named `as_str` found for reference `&'a str` in the current scope - --> $DIR/remove-as_str.rs:7:7 - | -LL | s.as_str(); - | -^^^^^^-- help: remove this method call - -error[E0599]: no method named `as_str` found for mutable reference `&mut str` in the current scope - --> $DIR/remove-as_str.rs:12:7 - | -LL | s.as_str(); - | -^^^^^^-- help: remove this method call - -error[E0599]: no method named `as_str` found for reference `&&str` in the current scope - --> $DIR/remove-as_str.rs:17:7 - | -LL | s.as_str(); - | -^^^^^^-- help: remove this method call - -error: aborting due to 4 previous errors - -For more information about this error, try `rustc --explain E0599`.