diff options
Diffstat (limited to 'src/tools/clippy/clippy_lints/src/methods/string_extend_chars.rs')
-rw-r--r-- | src/tools/clippy/clippy_lints/src/methods/string_extend_chars.rs | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/src/tools/clippy/clippy_lints/src/methods/string_extend_chars.rs b/src/tools/clippy/clippy_lints/src/methods/string_extend_chars.rs new file mode 100644 index 000000000..d06658f2a --- /dev/null +++ b/src/tools/clippy/clippy_lints/src/methods/string_extend_chars.rs @@ -0,0 +1,45 @@ +use clippy_utils::diagnostics::span_lint_and_sugg; +use clippy_utils::method_chain_args; +use clippy_utils::source::snippet_with_applicability; +use clippy_utils::ty::is_type_diagnostic_item; +use rustc_errors::Applicability; +use rustc_hir as hir; +use rustc_lint::LateContext; +use rustc_middle::ty; +use rustc_span::symbol::sym; + +use super::STRING_EXTEND_CHARS; + +pub(super) fn check(cx: &LateContext<'_>, expr: &hir::Expr<'_>, recv: &hir::Expr<'_>, arg: &hir::Expr<'_>) { + let obj_ty = cx.typeck_results().expr_ty(recv).peel_refs(); + if !is_type_diagnostic_item(cx, obj_ty, sym::String) { + return; + } + if let Some(arglists) = method_chain_args(arg, &["chars"]) { + let target = &arglists[0][0]; + let self_ty = cx.typeck_results().expr_ty(target).peel_refs(); + let ref_str = if *self_ty.kind() == ty::Str { + "" + } else if is_type_diagnostic_item(cx, self_ty, sym::String) { + "&" + } else { + return; + }; + + let mut applicability = Applicability::MachineApplicable; + span_lint_and_sugg( + cx, + STRING_EXTEND_CHARS, + expr.span, + "calling `.extend(_.chars())`", + "try this", + format!( + "{}.push_str({}{})", + snippet_with_applicability(cx, recv.span, "..", &mut applicability), + ref_str, + snippet_with_applicability(cx, target.span, "..", &mut applicability) + ), + applicability, + ); + } +} |