Auto merge of rust-lang#10103 - Niki4tap:overflow_ice, r=flip1995

Fix overflow ICE in large_stack/const_arrays

Change `maximum_allowed_size` config variable type from `u64` to `u128`, and converting total array sizes to `u128` to avoid overflow during multiplication.

Fixes rust-lang#10044

changelog: Fix: [`large_const_arrays`] and [`large_stack_arrays`]: avoid integer overflow when calculating total array size
rust-lang#10103

Author: bors

clippy_lints/src/large_const_arrays.rs

@@ -34,12 +34,12 @@ declare_clippy_lint! {
 }
 
 pub struct LargeConstArrays {
-    maximum_allowed_size: u64,
+    maximum_allowed_size: u128,
 }
 
 impl LargeConstArrays {
     #[must_use]
-    pub fn new(maximum_allowed_size: u64) -> Self {
+    pub fn new(maximum_allowed_size: u128) -> Self {
         Self { maximum_allowed_size }
     }
 }
@@ -56,7 +56,7 @@ impl<'tcx> LateLintPass<'tcx> for LargeConstArrays {
             if let ConstKind::Value(ty::ValTree::Leaf(element_count)) = cst.kind();
             if let Ok(element_count) = element_count.try_to_machine_usize(cx.tcx);
             if let Ok(element_size) = cx.layout_of(*element_type).map(|l| l.size.bytes());
-            if self.maximum_allowed_size < element_count * element_size;
+            if self.maximum_allowed_size < u128::from(element_count) * u128::from(element_size);
 
             then {
                 let hi_pos = item.ident.span.lo() - BytePos::from_usize(1);

clippy_lints/src/large_stack_arrays.rs

@@ -24,12 +24,12 @@ declare_clippy_lint! {
 }
 
 pub struct LargeStackArrays {
-    maximum_allowed_size: u64,
+    maximum_allowed_size: u128,
 }
 
 impl LargeStackArrays {
     #[must_use]
-    pub fn new(maximum_allowed_size: u64) -> Self {
+    pub fn new(maximum_allowed_size: u128) -> Self {
         Self { maximum_allowed_size }
     }
 }
@@ -45,7 +45,7 @@ impl<'tcx> LateLintPass<'tcx> for LargeStackArrays {
           && let Ok(element_size) = cx.layout_of(*element_type).map(|l| l.size.bytes())
           && !cx.tcx.hir().parent_iter(expr.hir_id)
               .any(|(_, node)| matches!(node, Node::Item(Item { kind: ItemKind::Static(..), .. })))
-          && self.maximum_allowed_size < element_count * element_size {
+          && self.maximum_allowed_size < u128::from(element_count) * u128::from(element_size) {
               span_lint_and_help(
                   cx,
                   LARGE_STACK_ARRAYS,

clippy_lints/src/utils/conf.rs

@@ -333,7 +333,7 @@ define_Conf! {
     /// Lint: LARGE_STACK_ARRAYS, LARGE_CONST_ARRAYS.
     ///
     /// The maximum allowed size for arrays on the stack
-    (array_size_threshold: u64 = 512_000),
+    (array_size_threshold: u128 = 512_000),
     /// Lint: VEC_BOX.
     ///
     /// The size of the boxed type in bytes, where boxing in a `Vec` is allowed

tests/ui/crashes/ice-10044.rs

@@ -0,0 +1,3 @@
+fn main() {
+    [0; usize::MAX];
+}

tests/ui/crashes/ice-10044.stderr

@@ -0,0 +1,10 @@
+error: statement with no effect
+  --> $DIR/ice-10044.rs:2:5
+   |
+LL |     [0; usize::MAX];
+   |     ^^^^^^^^^^^^^^^^
+   |
+   = note: `-D clippy::no-effect` implied by `-D warnings`
+
+error: aborting due to previous error
+