zig

commit f3544a707941269ec3ed9145ee1432df5a01a10a (tree)
parent 92505a7de7f720acc74906a053cd89a33174eb1f
Author: Robbie Lyman <rb.lymn@gmail.com>
Date:   Mon, 22 Jun 2026 08:49:46 -0400

fix: Allocator contract should allow free on single-pointer-to-array

Currently, when calling `free` a slice created by slicing a pointer with
comptime-known start and end, a compile-time assertion is hit, because
the slicing results in `*[len]T` rather than the expected `[]T`.

This commit allows `Allocator.free` to be called on such pointers as
well.

closes #35712

Diffstat:
M
lib/std/mem/Allocator.zig
 | 
5
++++-

1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/lib/std/mem/Allocator.zig b/lib/std/mem/Allocator.zig
@@ -445,7 +445,10 @@ pub fn reallocAdvanced(
 /// To free a single item, see `destroy`.
 pub fn free(self: Allocator, memory: anytype) void {
     const slice_info = @typeInfo(@TypeOf(memory)).pointer;
-    comptime assert(slice_info.size == .slice);
+    if (slice_info.size != .slice) {
+        // slicing with comptime-known start and end results in *[len]T, which may be free'd
+        comptime assert(slice_info.size == .one and @typeInfo(slice_info.child) == .array);
+    }
     const bytes: []u8 = @ptrCast(@constCast(mem.absorbSentinel(memory)));
     if (bytes.len == 0) return;
     @memset(bytes, undefined);