clarify comments and names in check_validity_requirement

Author: RalfJung

compiler/rustc_const_eval/src/util/check_validity_requirement.rs

@@ -32,15 +32,15 @@ pub fn check_validity_requirement<'tcx>(
 
     let layout_cx = LayoutCx { tcx, param_env: param_env_and_ty.param_env };
     if kind == ValidityRequirement::Uninit || tcx.sess.opts.unstable_opts.strict_init_checks {
-        might_permit_raw_init_strict(layout, &layout_cx, kind)
+        check_validity_requirement_strict(layout, &layout_cx, kind)
     } else {
-        might_permit_raw_init_lax(layout, &layout_cx, kind)
+        check_validity_requirement_lax(layout, &layout_cx, kind)
     }
 }
 
-/// Implements the 'strict' version of the `might_permit_raw_init` checks; see that function for
+/// Implements the 'strict' version of the `check_validity_requirement` checks; see that function for
 /// details.
-fn might_permit_raw_init_strict<'tcx>(
+fn check_validity_requirement_strict<'tcx>(
     ty: TyAndLayout<'tcx>,
     cx: &LayoutCx<'tcx, TyCtxt<'tcx>>,
     kind: ValidityRequirement,
@@ -65,6 +65,8 @@ fn might_permit_raw_init_strict<'tcx>(
     // This does *not* actually check that references are dereferenceable, but since all types that
     // require dereferenceability also require non-null, we don't actually get any false negatives
     // due to this.
+    // The value we are validating is temporary and discarded at the end of this function, so
+    // there is no point in reseting provenance and padding.
     Ok(cx
         .validate_operand(
             &allocated.into(),
@@ -74,9 +76,9 @@ fn might_permit_raw_init_strict<'tcx>(
         .is_ok())
 }
 
-/// Implements the 'lax' (default) version of the `might_permit_raw_init` checks; see that function for
+/// Implements the 'lax' (default) version of the `check_validity_requirement` checks; see that function for
 /// details.
-fn might_permit_raw_init_lax<'tcx>(
+fn check_validity_requirement_lax<'tcx>(
     this: TyAndLayout<'tcx>,
     cx: &LayoutCx<'tcx, TyCtxt<'tcx>>,
     init_kind: ValidityRequirement,
@@ -141,7 +143,7 @@ fn might_permit_raw_init_lax<'tcx>(
         }
         FieldsShape::Arbitrary { offsets, .. } => {
             for idx in 0..offsets.len() {
-                if !might_permit_raw_init_lax(this.field(cx, idx), cx, init_kind)? {
+                if !check_validity_requirement_lax(this.field(cx, idx), cx, init_kind)? {
                     // We found a field that is unhappy with this kind of initialization.
                     return Ok(false);
                 }