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

@@ -15,6 +15,7 @@ enum E {
     T(u32),
 }
 
+const STATIC_PROMOTED_LARGE_ARRAY: &[u8; 512001] = &[0; 512001];
 pub static DOESNOTLINT: [u8; 512_001] = [0; 512_001];
 pub static DOESNOTLINT2: [u8; 512_001] = {
     let x = 0;

tests/ui/large_stack_arrays.stderr

@@ -1,5 +1,5 @@
 error: allocating a local array larger than 512000 bytes
-  --> tests/ui/large_stack_arrays.rs:32:14
+  --> tests/ui/large_stack_arrays.rs:33:14
    |
 LL |     let _x = [build(); 3];
    |              ^^^^^^^^^^^^
@@ -9,63 +9,63 @@ LL |     let _x = [build(); 3];
    = help: to override `-D warnings` add `#[allow(clippy::large_stack_arrays)]`
 
 error: allocating a local array larger than 512000 bytes
-  --> tests/ui/large_stack_arrays.rs:35:14
+  --> tests/ui/large_stack_arrays.rs:36:14
    |
 LL |     let _y = [build(), build(), build()];
    |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider allocating on the heap with `vec![build(), build(), build()].into_boxed_slice()`
 
 error: allocating a local array larger than 512000 bytes
-  --> tests/ui/large_stack_arrays.rs:41:9
+  --> tests/ui/large_stack_arrays.rs:42:9
    |
 LL |         [0u32; 20_000_000],
    |         ^^^^^^^^^^^^^^^^^^
    |
    = help: consider allocating on the heap with `vec![0u32; 20_000_000].into_boxed_slice()`
 
 error: allocating a local array larger than 512000 bytes
-  --> tests/ui/large_stack_arrays.rs:43:9
+  --> tests/ui/large_stack_arrays.rs:44:9
    |
 LL |         [S { data: [0; 32] }; 5000],
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider allocating on the heap with `vec![S { data: [0; 32] }; 5000].into_boxed_slice()`
 
 error: allocating a local array larger than 512000 bytes
-  --> tests/ui/large_stack_arrays.rs:45:9
+  --> tests/ui/large_stack_arrays.rs:46:9
    |
 LL |         [Some(""); 20_000_000],
    |         ^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider allocating on the heap with `vec![Some(""); 20_000_000].into_boxed_slice()`
 
 error: allocating a local array larger than 512000 bytes
-  --> tests/ui/large_stack_arrays.rs:47:9
+  --> tests/ui/large_stack_arrays.rs:48:9
    |
 LL |         [E::T(0); 5000],
    |         ^^^^^^^^^^^^^^^
    |
    = help: consider allocating on the heap with `vec![E::T(0); 5000].into_boxed_slice()`
 
 error: allocating a local array larger than 512000 bytes
-  --> tests/ui/large_stack_arrays.rs:49:9
+  --> tests/ui/large_stack_arrays.rs:50:9
    |
 LL |         [0u8; usize::MAX],
    |         ^^^^^^^^^^^^^^^^^
    |
    = help: consider allocating on the heap with `vec![0u8; usize::MAX].into_boxed_slice()`
 
 error: allocating a local array larger than 512000 bytes
-  --> tests/ui/large_stack_arrays.rs:93:13
+  --> tests/ui/large_stack_arrays.rs:94:13
    |
 LL |     let y = [x, x, dummy!(x), x, x];
    |             ^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider allocating on the heap with `vec![x, x, dummy!(x), x, x].into_boxed_slice()`
 
 error: allocating a local array larger than 512000 bytes
-  --> tests/ui/large_stack_arrays.rs:70:13
+  --> tests/ui/large_stack_arrays.rs:71:13
    |
 LL |             [$a, $b, $a, $b]
    |             ^^^^^^^^^^^^^^^^
@@ -76,21 +76,21 @@ LL |     let y = dummy![x => x];
    = note: this error originates in the macro `dummy` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: allocating a local array larger than 512000 bytes
-  --> tests/ui/large_stack_arrays.rs:98:20
+  --> tests/ui/large_stack_arrays.rs:99:20
    |
 LL |     let y = dummy![[x, x, x, x, x]];
    |                    ^^^^^^^^^^^^^^^
    |
    = help: consider allocating on the heap with `vec![x, x, x, x, x].into_boxed_slice()`
 
 error: allocating a local array larger than 512000 bytes
-  --> tests/ui/large_stack_arrays.rs:101:39
+  --> tests/ui/large_stack_arrays.rs:102:39
    |
 LL |     let y = proc_macros::make_it_big!([x; 1]);
    |                                       ^^^^^^
 
 error: allocating a local array larger than 512000 bytes
-  --> tests/ui/large_stack_arrays.rs:82:23
+  --> tests/ui/large_stack_arrays.rs:83:23
    |
 LL |             let _x_ = [$id; $n];
    |                       ^^^^^^^^^