Allow raw identifiers e.g. r#mod (#149)

* Allow raw identifiers

* Fix UI tests

* UI tests with latest nightly

* Add UI test

src/ty/path.rs

@@ -205,6 +205,16 @@ mod tests {
         );
     }
 
+    #[test]
+    fn path_with_raw_identifers_ok() {
+        assert_eq!(
+            Path::from_segments(vec!["r#mod", "r#Struct"]),
+            Ok(Path {
+                segments: vec!["r#mod", "r#Struct"]
+            })
+        );
+    }
+
     #[test]
     fn path_err() {
         assert_eq!(Path::from_segments(vec![]), Err(PathError::MissingSegments));

src/utils.rs

@@ -19,7 +19,9 @@ pub fn is_rust_identifier(s: &str) -> bool {
     if !s.is_ascii() {
         return false
     }
-    if let Some((&head, tail)) = s.as_bytes().split_first() {
+    // Trim valid raw identifier prefix
+    let trimmed = s.trim_start_matches("r#");
+    if let Some((&head, tail)) = trimmed.as_bytes().split_first() {
         // Check if head and tail make up a proper Rust identifier.
         let head_ok = head == b'_'
             || (b'a'..=b'z').contains(&head)

test_suite/tests/ui/fail_missing_derive.stderr

@@ -4,6 +4,16 @@ error[E0277]: the trait bound `PawType<u16>: TypeInfo` is not satisfied
 19 |     assert_type_info::<Cat<bool, u8, u16>>();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `TypeInfo` is not implemented for `PawType<u16>`
    |
+   = help: the following other types implement trait `TypeInfo`:
+             &T
+             &mut T
+             ()
+             (A, B)
+             (A, B, C)
+             (A, B, C, D)
+             (A, B, C, D, E)
+             (A, B, C, D, E, F)
+           and 54 others
 note: required because of the requirements on the impl of `TypeInfo` for `Cat<bool, u8, u16>`
   --> tests/ui/fail_missing_derive.rs:8:10
    |

test_suite/tests/ui/fail_unions.stderr

@@ -14,6 +14,16 @@ error[E0277]: the trait bound `Commonwealth: TypeInfo` is not satisfied
 14 |     assert_type_info::<Commonwealth>();
    |                        ^^^^^^^^^^^^ the trait `TypeInfo` is not implemented for `Commonwealth`
    |
+   = help: the following other types implement trait `TypeInfo`:
+             &T
+             &mut T
+             ()
+             (A, B)
+             (A, B, C)
+             (A, B, C, D)
+             (A, B, C, D, E)
+             (A, B, C, D, E, F)
+           and 53 others
 note: required by a bound in `assert_type_info`
   --> tests/ui/fail_unions.rs:11:24
    |

test_suite/tests/ui/pass_raw_identifers.rs

@@ -0,0 +1,21 @@
+use info::{self as scale_info};
+use scale_info::TypeInfo;
+
+#[allow(dead_code, non_camel_case_types)]
+mod r#mod {
+    use super::*;
+    #[derive(TypeInfo)]
+    pub enum r#enum {
+        r#true,
+    }
+    #[derive(TypeInfo)]
+    pub struct r#struct {
+        r#try: r#enum,
+    }
+}
+
+fn assert_type_info<T: TypeInfo + 'static>() {}
+
+fn main() {
+    assert_type_info::<r#mod::r#struct>();
+}