diff --git a/clippy_lints/src/strings.rs b/clippy_lints/src/strings.rs index c0be724bcdee..509ad4e4fcb3 100644 --- a/clippy_lints/src/strings.rs +++ b/clippy_lints/src/strings.rs @@ -5,6 +5,7 @@ use clippy_utils::{ SpanlessEq, get_expr_use_or_unification_node, get_parent_expr, is_lint_allowed, method_calls, peel_blocks, sym, }; use rustc_errors::Applicability; +use rustc_hir::def::{DefKind, Res}; use rustc_hir::def_id::DefId; use rustc_hir::{BinOpKind, BorrowKind, Expr, ExprKind, LangItem, Node}; use rustc_lint::{LateContext, LateLintPass, LintContext}; @@ -410,6 +411,23 @@ impl<'tcx> LateLintPass<'tcx> for StrToString { diag.span_suggestion(expr.span, "try", format!("{snippet}.to_owned()"), applicability); }, ); + } else if let ExprKind::Path(_) = expr.kind + && let Some(parent) = get_parent_expr(cx, expr) + && let ExprKind::Call(_, args) | ExprKind::MethodCall(_, _, args, _) = &parent.kind + && args.iter().any(|a| a.hir_id == expr.hir_id) + && let Res::Def(DefKind::AssocFn, def_id) = expr.res(cx) + && cx.tcx.is_diagnostic_item(sym::to_string_method, def_id) + { + // Detected `ToString::to_string` passed as an argument (generic: any call or method call) + span_lint_and_sugg( + cx, + STR_TO_STRING, + expr.span, + "`ToString::to_string` used as `&str` to `String` converter", + "try", + "ToOwned::to_owned".to_string(), + Applicability::MachineApplicable, + ); } } } diff --git a/tests/ui/str_to_string.fixed b/tests/ui/str_to_string.fixed index 8713c4f9bc86..5b76cf78f069 100644 --- a/tests/ui/str_to_string.fixed +++ b/tests/ui/str_to_string.fixed @@ -22,3 +22,32 @@ fn issue16271(key: &[u8]) { let _value = t!(str::from_utf8(key)).to_owned(); //~^ str_to_string } + +struct GenericWrapper(T); + +impl GenericWrapper { + fn mapper U>(self, f: F) -> U { + f(self.0) + } +} + +fn issue16511(x: Option<&str>) { + let _ = x.map(ToOwned::to_owned); + //~^ str_to_string + + let _ = x.map(ToOwned::to_owned); + //~^ str_to_string + + let _ = ["a", "b"].iter().map(ToOwned::to_owned); + //~^ str_to_string + + fn mapper String>(f: F) -> String { + f("hello") + } + let _ = mapper(ToOwned::to_owned); + //~^ str_to_string + + let w = GenericWrapper("hello"); + let _ = w.mapper(ToOwned::to_owned); + //~^ str_to_string +} diff --git a/tests/ui/str_to_string.rs b/tests/ui/str_to_string.rs index b81759e1037b..f099eb29b1b5 100644 --- a/tests/ui/str_to_string.rs +++ b/tests/ui/str_to_string.rs @@ -22,3 +22,32 @@ fn issue16271(key: &[u8]) { let _value = t!(str::from_utf8(key)).to_string(); //~^ str_to_string } + +struct GenericWrapper(T); + +impl GenericWrapper { + fn mapper U>(self, f: F) -> U { + f(self.0) + } +} + +fn issue16511(x: Option<&str>) { + let _ = x.map(ToString::to_string); + //~^ str_to_string + + let _ = x.map(str::to_string); + //~^ str_to_string + + let _ = ["a", "b"].iter().map(ToString::to_string); + //~^ str_to_string + + fn mapper String>(f: F) -> String { + f("hello") + } + let _ = mapper(ToString::to_string); + //~^ str_to_string + + let w = GenericWrapper("hello"); + let _ = w.mapper(ToString::to_string); + //~^ str_to_string +} diff --git a/tests/ui/str_to_string.stderr b/tests/ui/str_to_string.stderr index c0a38c8ebe46..296b8e36f28c 100644 --- a/tests/ui/str_to_string.stderr +++ b/tests/ui/str_to_string.stderr @@ -19,5 +19,35 @@ error: `to_string()` called on a `&str` LL | let _value = t!(str::from_utf8(key)).to_string(); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `t!(str::from_utf8(key)).to_owned()` -error: aborting due to 3 previous errors +error: `ToString::to_string` used as `&str` to `String` converter + --> tests/ui/str_to_string.rs:35:19 + | +LL | let _ = x.map(ToString::to_string); + | ^^^^^^^^^^^^^^^^^^^ help: try: `ToOwned::to_owned` + +error: `ToString::to_string` used as `&str` to `String` converter + --> tests/ui/str_to_string.rs:38:19 + | +LL | let _ = x.map(str::to_string); + | ^^^^^^^^^^^^^^ help: try: `ToOwned::to_owned` + +error: `ToString::to_string` used as `&str` to `String` converter + --> tests/ui/str_to_string.rs:41:35 + | +LL | let _ = ["a", "b"].iter().map(ToString::to_string); + | ^^^^^^^^^^^^^^^^^^^ help: try: `ToOwned::to_owned` + +error: `ToString::to_string` used as `&str` to `String` converter + --> tests/ui/str_to_string.rs:47:20 + | +LL | let _ = mapper(ToString::to_string); + | ^^^^^^^^^^^^^^^^^^^ help: try: `ToOwned::to_owned` + +error: `ToString::to_string` used as `&str` to `String` converter + --> tests/ui/str_to_string.rs:51:22 + | +LL | let _ = w.mapper(ToString::to_string); + | ^^^^^^^^^^^^^^^^^^^ help: try: `ToOwned::to_owned` + +error: aborting due to 8 previous errors