Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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,
+        );
+    }
+}