add regression test for Self in flags values

tests/compile-fail/bitflags_custom_bits.rs

@@ -19,7 +19,7 @@ use std::{
     },
 };
 
-use bitflags::{bitflags, Bits, parser::{ParseError, FromHex}};
+use bitflags::{bitflags, Bits, parser::{ParseError, ParseHex}};
 
 // Ideally we'd actually want this to work, but currently need something like `num`'s `Zero`
 // With some design work it could be made possible
@@ -117,8 +117,8 @@ impl Binary for MyInt {
     }
 }
 
-impl FromHex for MyInt {
-    fn from_hex(input: &str) -> Result<Self, ParseError> {
+impl ParseHex for MyInt {
+    fn parse_hex(input: &str) -> Result<Self, ParseError> {
         Ok(MyInt(u8::from_str_radix(input, 16).map_err(|_| ParseError::invalid_hex_flag(input))?))
     }
 }

tests/compile-fail/bitflags_custom_bits.stderr

@@ -20,6 +20,38 @@ note: required by a bound in `PublicFlags::Primitive`
     |     type Primitive: Primitive;
     |                     ^^^^^^^^^ required by this bound in `PublicFlags::Primitive`
 
+error[E0277]: the trait bound `MyInt: WriteHex` is not satisfied
+   --> tests/compile-fail/bitflags_custom_bits.rs:126:1
+    |
+126 | / bitflags! {
+127 | |     struct Flags128: MyInt {
+128 | |         const A = MyInt(0b0000_0001u8);
+129 | |         const B = MyInt(0b0000_0010u8);
+130 | |         const C = MyInt(0b0000_0100u8);
+131 | |     }
+132 | | }
+    | | ^
+    | | |
+    | |_the trait `WriteHex` is not implemented for `MyInt`
+    |   required by a bound introduced by this call
+    |
+    = help: the following other types implement trait `WriteHex`:
+              i128
+              i16
+              i32
+              i64
+              i8
+              isize
+              u128
+              u16
+            and $N others
+note: required by a bound in `to_writer`
+   --> src/parser.rs
+    |
+    |     B::Bits: WriteHex,
+    |              ^^^^^^^^ required by this bound in `to_writer`
+    = note: this error originates in the macro `__impl_internal_bitflags` which comes from the expansion of the macro `bitflags` (in Nightly builds, run with -Z macro-backtrace for more info)
+
 error[E0277]: can't compare `MyInt` with `_` in const contexts
    --> tests/compile-fail/bitflags_custom_bits.rs:126:1
     |

tests/compile-pass/bitflags_self_in_value.rs

@@ -0,0 +1,15 @@
+use bitflags::bitflags;
+
+bitflags! {
+    pub struct Flags: u32 {
+        const SOME_FLAG = 1 << Self::SOME_FLAG_SHIFT;
+    }
+}
+
+impl Flags {
+    const SOME_FLAG_SHIFT: u32 = 5;
+}
+
+fn main() {
+
+}