Update upstream source from tag 'upstream/1.52.1+dfsg1'

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

diff --git a/src/tools/clippy/clippy_lints/src/methods/filter_map_next.rs b/src/tools/clippy/clippy_lints/src/methods/filter_map_next.rs
new file mode 100644 (file)
index 0000000..a789df9
--- /dev/null
+++ b/src/tools/clippy/clippy_lints/src/methods/filter_map_next.rs
@@ -0,0 +1,40 @@
+use crate::utils::{match_trait_method, meets_msrv, paths, snippet, span_lint, span_lint_and_sugg};
+use rustc_errors::Applicability;
+use rustc_hir as hir;
+use rustc_lint::LateContext;
+use rustc_semver::RustcVersion;
+
+use super::FILTER_MAP_NEXT;
+
+const FILTER_MAP_NEXT_MSRV: RustcVersion = RustcVersion::new(1, 30, 0);
+
+pub(super) fn check<'tcx>(
+    cx: &LateContext<'tcx>,
+    expr: &'tcx hir::Expr<'_>,
+    filter_args: &'tcx [hir::Expr<'_>],
+    msrv: Option<&RustcVersion>,
+) {
+    if match_trait_method(cx, expr, &paths::ITERATOR) {
+        if !meets_msrv(msrv, &FILTER_MAP_NEXT_MSRV) {
+            return;
+        }
+
+        let msg = "called `filter_map(..).next()` on an `Iterator`. This is more succinctly expressed by calling \
+                   `.find_map(..)` instead";
+        let filter_snippet = snippet(cx, filter_args[1].span, "..");
+        if filter_snippet.lines().count() <= 1 {
+            let iter_snippet = snippet(cx, filter_args[0].span, "..");
+            span_lint_and_sugg(
+                cx,
+                FILTER_MAP_NEXT,
+                expr.span,
+                msg,
+                "try this",
+                format!("{}.find_map({})", iter_snippet, filter_snippet),
+                Applicability::MachineApplicable,
+            );
+        } else {
+            span_lint(cx, FILTER_MAP_NEXT, expr.span, msg);
+        }
+    }
+}