FIX #1571: For rust-target >= 1.30, make __BindgenBitfieldUnit::new a const fn

Author: Wallacoloo

src/codegen/bitfield_unit.rs

@@ -9,7 +9,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align>
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align>
 {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self {
             storage,
             align: [],

src/codegen/mod.rs

@@ -410,7 +410,7 @@ impl CodeGenerator for Module {
                     utils::prepend_objc_header(ctx, &mut *result);
                 }
                 if result.saw_bitfield_unit {
-                    utils::prepend_bitfield_unit_type(&mut *result);
+                    utils::prepend_bitfield_unit_type(ctx, &mut *result);
                 }
             }
         };
@@ -3591,11 +3591,21 @@ mod utils {
     use ir::item::{Item, ItemCanonicalPath};
     use ir::ty::TypeKind;
     use proc_macro2;
+    use std::borrow::Cow;
     use std::mem;
     use std::str::FromStr;
 
-    pub fn prepend_bitfield_unit_type(result: &mut Vec<proc_macro2::TokenStream>) {
-        let bitfield_unit_type = proc_macro2::TokenStream::from_str(include_str!("./bitfield_unit.rs")).unwrap();
+    pub fn prepend_bitfield_unit_type(
+        ctx: &BindgenContext,
+        result: &mut Vec<proc_macro2::TokenStream>
+    ) {
+        let bitfield_unit_src = include_str!("./bitfield_unit.rs");
+        let bitfield_unit_src = if ctx.options().rust_features().min_const_fn {
+            Cow::Borrowed(bitfield_unit_src)
+        } else {
+            Cow::Owned(bitfield_unit_src.replace("const fn ", "fn "))
+        };
+        let bitfield_unit_type = proc_macro2::TokenStream::from_str(&bitfield_unit_src).unwrap();
         let bitfield_unit_type = quote!(#bitfield_unit_type);
 
         let items = vec![bitfield_unit_type];

src/features.rs

@@ -102,6 +102,8 @@ macro_rules! rust_target_base {
             => Stable_1_27 => 1.27;
             /// Rust stable 1.28
             => Stable_1_28 => 1.28;
+            /// Rust stable 1.30
+            => Stable_1_30 => 1.30;
             /// Rust stable 1.33
             => Stable_1_33 => 1.33;
             /// Nightly rust
@@ -192,6 +194,11 @@ rust_feature_def!(
         /// repr(transparent) ([PR](https://github.com/rust-lang/rust/pull/51562))
         => repr_transparent;
     }
+    Stable_1_30 {
+        /// `const fn` support for limited cases
+        /// ([PR](https://github.com/rust-lang/rust/pull/54835/)
+        => min_const_fn;
+    }
     Stable_1_33 {
         /// repr(packed(N)) ([PR](https://github.com/rust-lang/rust/pull/57049))
         => repr_packed_n;

tests/expectations/tests/bitfield-32bit-overflow.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/bitfield-large.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/bitfield-method-same-name.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/bitfield_align.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/bitfield_align_2.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/bitfield_method_mangling.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/derive-bitfield-method-same-name.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/derive-debug-bitfield-core.rs

@@ -17,7 +17,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/derive-debug-bitfield.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/derive-partialeq-bitfield.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/divide-by-zero-in-struct-layout.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/issue-1034.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/issue-1076-unnamed-bitfield-alignment.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/issue-739-pointer-wide-bitfield.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/issue-816.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/jsval_layout_opaque.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/layout_align.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/layout_eth_conf.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/layout_mbuf.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/only_bitfields.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/struct_with_bitfields.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/union_bitfield.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/union_with_anon_struct_bitfield.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }

tests/expectations/tests/weird_bitfields.rs

@@ -15,7 +15,7 @@ pub struct __BindgenBitfieldUnit<Storage, Align> {
 }
 impl<Storage, Align> __BindgenBitfieldUnit<Storage, Align> {
     #[inline]
-    pub fn new(storage: Storage) -> Self {
+    pub const fn new(storage: Storage) -> Self {
         Self { storage, align: [] }
     }
 }