diff options
Diffstat (limited to 'clippy_lints/src/slow_vector_initialization.rs')
| -rw-r--r-- | clippy_lints/src/slow_vector_initialization.rs | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/clippy_lints/src/slow_vector_initialization.rs b/clippy_lints/src/slow_vector_initialization.rs index c9ab622ad25..9db18c2976c 100644 --- a/clippy_lints/src/slow_vector_initialization.rs +++ b/clippy_lints/src/slow_vector_initialization.rs @@ -1,4 +1,5 @@ use clippy_utils::diagnostics::span_lint_and_then; +use clippy_utils::macros::root_macro_call; use clippy_utils::sugg::Sugg; use clippy_utils::{ get_enclosing_block, is_expr_path_def_path, is_integer_literal, is_path_diagnostic_item, path_to_local, @@ -148,6 +149,15 @@ impl SlowVectorInit { /// - `Some(InitializedSize::Uninitialized)` for `Vec::new()` /// - `None` for other, unrelated kinds of expressions fn as_vec_initializer<'tcx>(cx: &LateContext<'_>, expr: &'tcx Expr<'tcx>) -> Option<InitializedSize<'tcx>> { + // Generally don't warn if the vec initializer comes from an expansion, except for the vec! macro. + // This lets us still warn on `vec![]`, while ignoring other kinds of macros that may output an + // empty vec + if expr.span.from_expansion() + && root_macro_call(expr.span).map(|m| m.def_id) != cx.tcx.get_diagnostic_item(sym::vec_macro) + { + return None; + } + if let ExprKind::Call(func, [len_expr]) = expr.kind && is_expr_path_def_path(cx, func, &paths::VEC_WITH_CAPACITY) { @@ -205,7 +215,7 @@ impl SlowVectorInit { span_lint_and_then(cx, SLOW_VECTOR_INITIALIZATION, slow_fill.span, msg, |diag| { diag.span_suggestion( - vec_alloc.allocation_expr.span, + vec_alloc.allocation_expr.span.source_callsite(), "consider replacing this with", format!("vec![0; {len_expr}]"), Applicability::Unspecified, |