Switch from expect to allow

Trouble with expect, but allow is already used anyway

Author: bushrat011899

naga/src/back/mod.rs

@@ -47,10 +47,10 @@ pub type NeedBakeExpressions = crate::FastHashSet<crate::Handle<crate::Expressio
 /// [`Expression`]: crate::Expression
 /// [`Handle`]: crate::Handle
 #[cfg_attr(
-    not(any(hlsl_out, msl_out, spv_out, glsl_out)),
-    expect(
+    not(any(glsl_out, hlsl_out, msl_out, wgsl_out)),
+    allow(
         dead_code,
-        reason = "only used with any of the aforementioned configurations"
+        reason = "shared helpers can be dead if none of the enabled backends need it"
     )
 )]
 struct Baked(crate::Handle<crate::Expression>);