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Add error for bad cast from *T to *[n]T

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Casting `*T` to `*[1]T` should still work, but every other length
will now be a compiler error instead of a potential OOB access.
This commit is contained in:
InKryption 2023-03-16 01:02:10 +01:00 committed by Veikka Tuominen
parent e1e414e62a
commit 9964f1c160
2 changed files with 19 additions and 0 deletions
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1
src/Sema.zig
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@ -24853,6 +24853,7 @@ fn coerceExtra(
const array_ty = dest_info.pointee_type;
if (array_ty.zigTypeTag() != .Array) break :single_item;
const array_elem_ty = array_ty.childType();
if (array_ty.arrayLen() != 1) break :single_item;
const dest_is_mut = dest_info.mutable;
switch (try sema.coerceInMemoryAllowed(block, array_elem_ty, ptr_elem_ty, dest_is_mut, target, dest_ty_src, inst_src)) {
.ok => {},

18
test/cases/compile_errors/attempted_implicit_cast_from_T_to_long_array_ptr.zig Normal file
View File

@ -0,0 +1,18 @@
export fn entry0(single: *u32) void {
_ = @as(*const [0]u32, single);
}
export fn entry1(single: *u32) void {
_ = @as(*const [1]u32, single);
}
export fn entry2(single: *u32) void {
_ = @as(*const [2]u32, single);
}
// error
// backend=stage2
// target=native
//
// :2:28: error: expected type '*const [0]u32', found '*u32'
// :2:28: note: pointer type child 'u32' cannot cast into pointer type child '[0]u32'
// :8:28: error: expected type '*const [2]u32', found '*u32'
// :8:28: note: pointer type child 'u32' cannot cast into pointer type child '[2]u32'