pep440: move VersionSpecifiersError to version_specifiers module

Since it's specifier to version specifier parsing, it makes sense to
have it live with the corresponding type. Putting it in lib.rs I think
makes it seem like an error type that applies to other things as well.

crates/pep440-rs/src/lib.rs

@@ -44,7 +44,9 @@
 
 pub use {
     version::{LocalSegment, Operator, PreRelease, Version},
-    version_specifier::{parse_version_specifiers, VersionSpecifier, VersionSpecifiers},
+    version_specifier::{
+        parse_version_specifiers, VersionSpecifier, VersionSpecifiers, VersionSpecifiersParseError,
+    },
 };
 
 #[cfg(feature = "pyo3")]
@@ -55,36 +57,6 @@ pub use version::PyVersion;
 mod version;
 mod version_specifier;
 
-/// Error with span information (unicode width) inside the parsed line
-#[derive(Debug, Eq, PartialEq, Clone)]
-pub struct VersionSpecifiersParseError {
-    /// The actual error message
-    message: String,
-    /// The string that failed to parse
-    line: String,
-    /// The starting byte offset into the original string where the error
-    /// occurred.
-    start: usize,
-    /// The ending byte offset into the original string where the error
-    /// occurred.
-    end: usize,
-}
-
-impl std::fmt::Display for VersionSpecifiersParseError {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        use unicode_width::UnicodeWidthStr;
-
-        writeln!(f, "Failed to parse version: {}:", self.message)?;
-        writeln!(f, "{}", self.line)?;
-        let indent = self.line[..self.start].width();
-        let point = self.line[self.start..self.end].width();
-        writeln!(f, "{}{}", " ".repeat(indent), "^".repeat(point))?;
-        Ok(())
-    }
-}
-
-impl std::error::Error for VersionSpecifiersParseError {}
-
 /// Python bindings shipped as `pep440_rs`
 #[cfg(feature = "pyo3")]
 #[pymodule]

crates/pep440-rs/src/version_specifier.rs

@@ -14,7 +14,7 @@ use serde::{de, Deserialize, Deserializer, Serialize, Serializer};
 
 #[cfg(feature = "pyo3")]
 use crate::version::PyVersion;
-use crate::{version, Operator, Version, VersionSpecifiersParseError};
+use crate::{version, Operator, Version};
 
 /// A thin wrapper around `Vec<VersionSpecifier>` with a serde implementation
 ///
@@ -183,6 +183,36 @@ impl Serialize for VersionSpecifiers {
     }
 }
 
+/// Error with span information (unicode width) inside the parsed line
+#[derive(Debug, Eq, PartialEq, Clone)]
+pub struct VersionSpecifiersParseError {
+    /// The actual error message
+    message: String,
+    /// The string that failed to parse
+    line: String,
+    /// The starting byte offset into the original string where the error
+    /// occurred.
+    start: usize,
+    /// The ending byte offset into the original string where the error
+    /// occurred.
+    end: usize,
+}
+
+impl std::fmt::Display for VersionSpecifiersParseError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        use unicode_width::UnicodeWidthStr;
+
+        writeln!(f, "Failed to parse version: {}:", self.message)?;
+        writeln!(f, "{}", self.line)?;
+        let indent = self.line[..self.start].width();
+        let point = self.line[self.start..self.end].width();
+        writeln!(f, "{}{}", " ".repeat(indent), "^".repeat(point))?;
+        Ok(())
+    }
+}
+
+impl std::error::Error for VersionSpecifiersParseError {}
+
 /// A version range such such as `>1.2.3`, `<=4!5.6.7-a8.post9.dev0` or `== 4.1.*`. Parse with
 /// `VersionSpecifier::from_str`
 ///