Merge remote-tracking branch 'upstream/master' into rustup

[rust.git] / clippy_lints / src / methods / unnecessary_lazy_eval.rs

diff --git a/clippy_lints/src/methods/unnecessary_lazy_eval.rs b/clippy_lints/src/methods/unnecessary_lazy_eval.rs
index cde89983a2656aff2d0a50eb646b690699a79c6b..40ccb8c80b342aa758a3e905b748d147b0a3640f 100644 (file)
--- a/clippy_lints/src/methods/unnecessary_lazy_eval.rs
+++ b/clippy_lints/src/methods/unnecessary_lazy_eval.rs
@@ -33,20 +33,31 @@ pub(super) fn lint<'tcx>(
                 } else {
                     "unnecessary closure used to substitute value for `Result::Err`"
                 };
+                let applicability = if body
+                    .params
+                    .iter()
+                    // bindings are checked to be unused above
+                    .all(|param| matches!(param.pat.kind, hir::PatKind::Binding(..) | hir::PatKind::Wild))
+                {
+                    Applicability::MachineApplicable
+                } else {
+                    // replacing the lambda may break type inference
+                    Applicability::MaybeIncorrect
+                };
 
                 span_lint_and_sugg(
                     cx,
                     UNNECESSARY_LAZY_EVALUATIONS,
                     expr.span,
                     msg,
-                    &format!("Use `{}` instead", simplify_using),
+                    &format!("use `{}` instead", simplify_using),
                     format!(
                         "{0}.{1}({2})",
                         snippet(cx, args[0].span, ".."),
                         simplify_using,
                         snippet(cx, body_expr.span, ".."),
                     ),
-                    Applicability::MachineApplicable,
+                    applicability,
                 );
             }
         }