Guideline about word order

Author: dtolnay

src/checklist.md

@@ -10,6 +10,7 @@
   - [ ] Ownership suffixes use `_mut` and `_ref` ([C-OWN-SUFFIX])
   - [ ] Single-element containers implement appropriate getters ([C-GETTERS])
   - [ ] Feature names are free of placeholder words ([C-FEATURE])
+  - [ ] Names use a consistent word order ([C-WORD-ORDER])
 - **Interoperability** *(crate interacts nicely with other library functionality)*
   - [ ] Types eagerly implement common traits ([C-COMMON-TRAITS])
     - `Copy`, `Clone`, `Eq`, `PartialEq`, `Ord`, `PartialOrd`, `Hash`, `Debug`,
@@ -80,6 +81,7 @@
 [C-OWN-SUFFIX]: naming.html#c-own-suffix
 [C-GETTERS]: naming.html#c-getters
 [C-FEATURE]: naming.html#c-feature
+[C-WORD-ORDER]: naming.html#c-word-order
 
 [C-COMMON-TRAITS]: interoperability.html#c-common-traits
 [C-CONV-TRAITS]: interoperability.html#c-conv-traits

src/naming.md

@@ -303,3 +303,25 @@ we like for explicit features to behave the same way.
 
 As a related note, Cargo requires that features are additive so a feature named
 negatively like `no-abc` is practically never correct.
+
+
+<a id="c-word-order"></a>
+## Names use a consistent word order (C-WORD-ORDER)
+
+Here are some error types from the standard library:
+
+- [`JoinPathsError`](https://doc.rust-lang.org/std/env/struct.JoinPathsError.html)
+- [`ParseBoolError`](https://doc.rust-lang.org/std/str/struct.ParseBoolError.html)
+- [`ParseCharError`](https://doc.rust-lang.org/std/char/struct.ParseCharError.html)
+- [`ParseFloatError`](https://doc.rust-lang.org/std/num/struct.ParseFloatError.html)
+- [`ParseIntError`](https://doc.rust-lang.org/std/num/struct.ParseIntError.html)
+- [`RecvTimeoutError`](https://doc.rust-lang.org/std/sync/mpsc/enum.RecvTimeoutError.html)
+- [`StripPrefixError`](https://doc.rust-lang.org/std/path/struct.StripPrefixError.html)
+
+All of these use verb-object-error word order. If we were adding an error to
+represent an address failing to parse, for consistency we would want to name it
+in verb-object-error order like `ParseAddrError` rather than `AddrParseError`.
+
+The particular choice of word order is not important, but pay attention to
+consistency within the crate and consistency with similar functionality in the
+standard library.