Fix large_stack_arrays triggering for static/constants

Author: GnomedDev

clippy_lints/src/large_stack_arrays.rs

@@ -30,13 +30,15 @@ declare_clippy_lint! {
 pub struct LargeStackArrays {
     maximum_allowed_size: u64,
     prev_vec_macro_callsite: Option<Span>,
+    is_in_const_item: bool,
 }
 
 impl LargeStackArrays {
     pub fn new(conf: &'static Conf) -> Self {
         Self {
             maximum_allowed_size: conf.array_size_threshold,
             prev_vec_macro_callsite: None,
+            is_in_const_item: false,
         }
     }
 
@@ -60,8 +62,21 @@ impl LargeStackArrays {
 impl_lint_pass!(LargeStackArrays => [LARGE_STACK_ARRAYS]);
 
 impl<'tcx> LateLintPass<'tcx> for LargeStackArrays {
+    fn check_item(&mut self, _: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
+        if matches!(item.kind, ItemKind::Static(..) | ItemKind::Const(..)) {
+            self.is_in_const_item = true;
+        }
+    }
+
+    fn check_item_post(&mut self, _: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
+        if matches!(item.kind, ItemKind::Static(..) | ItemKind::Const(..)) {
+            self.is_in_const_item = false;
+        }
+    }
+
     fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &Expr<'tcx>) {
-        if let ExprKind::Repeat(_, _) | ExprKind::Array(_) = expr.kind
+        if !self.is_in_const_item
+            && let ExprKind::Repeat(_, _) | ExprKind::Array(_) = expr.kind
             && !self.is_from_vec_macro(cx, expr.span)
             && let ty::Array(element_type, cst) = cx.typeck_results().expr_ty(expr).kind()
             && let ConstKind::Value(_, ty::ValTree::Leaf(element_count)) = cst.kind()

tests/ui-toml/array_size_threshold/array_size_threshold.stderr

@@ -9,23 +9,15 @@ LL | const ABOVE: [u8; 11] = [0; 11];
    = note: `-D clippy::large-const-arrays` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::large_const_arrays)]`
 
-error: allocating a local array larger than 10 bytes
-  --> tests/ui-toml/array_size_threshold/array_size_threshold.rs:4:25
-   |
-LL | const ABOVE: [u8; 11] = [0; 11];
-   |                         ^^^^^^^
-   |
-   = help: consider allocating on the heap with `vec![0; 11].into_boxed_slice()`
-   = note: `-D clippy::large-stack-arrays` implied by `-D warnings`
-   = help: to override `-D warnings` add `#[allow(clippy::large_stack_arrays)]`
-
 error: allocating a local array larger than 10 bytes
   --> tests/ui-toml/array_size_threshold/array_size_threshold.rs:8:17
    |
 LL |     let above = [0u8; 11];
    |                 ^^^^^^^^^
    |
    = help: consider allocating on the heap with `vec![0u8; 11].into_boxed_slice()`
+   = note: `-D clippy::large-stack-arrays` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::large_stack_arrays)]`
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 

tests/ui/large_stack_arrays.rs

@@ -103,3 +103,5 @@ fn issue_12586() {
     let y = vec![proc_macros::make_it_big!([x; 10])];
     let y = vec![create_then_move![x; 5]; 5];
 }
+
+const STATIC_PROMOTED_LARGE_ARRAY: &[u8; 512001] = &[0; 512001];