Merge tag 'debian/1.52.1+dfsg1-1_exp2' into proxmox/buster

[rustc.git] / src / tools / clippy / clippy_lints / src / methods / iter_cloned_collect.rs

diff --git a/src/tools/clippy/clippy_lints/src/methods/iter_cloned_collect.rs b/src/tools/clippy/clippy_lints/src/methods/iter_cloned_collect.rs
new file mode 100644 (file)
index 0000000..c3e48ff
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/iter_cloned_collect.rs
@@ -0,0 +1,30 @@
+use crate::methods::derefs_to_slice;
+use crate::utils::{is_type_diagnostic_item, span_lint_and_sugg};
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir as hir;
+use rustc_lint::LateContext;
+use rustc_span::sym;
+
+use super::ITER_CLONED_COLLECT;
+
+pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, expr: &hir::Expr<'_>, iter_args: &'tcx [hir::Expr<'_>]) {
+    if_chain! {
+        if is_type_diagnostic_item(cx, cx.typeck_results().expr_ty(expr), sym::vec_type);
+        if let Some(slice) = derefs_to_slice(cx, &iter_args[0], cx.typeck_results().expr_ty(&iter_args[0]));
+        if let Some(to_replace) = expr.span.trim_start(slice.span.source_callsite());
+
+        then {
+            span_lint_and_sugg(
+                cx,
+                ITER_CLONED_COLLECT,
+                to_replace,
+                "called `iter().cloned().collect()` on a slice to create a `Vec`. Calling `to_vec()` is both faster and \
+                more readable",
+                "try",
+                ".to_vec()".to_string(),
+                Applicability::MachineApplicable,
+            );
+        }
+    }
+}