fix(manifest): Improve error on good pre-release

Author: epage

src/cargo/util/semver_ext.rs

@@ -142,10 +142,10 @@ impl std::str::FromStr for PartialVersion {
         let version_req = match semver::VersionReq::parse(value) {
             // Exclude semver operators like `^` and pre-release identifiers
             Ok(req) if value.chars().all(|c| c.is_ascii_digit() || c == '.') => req,
-            Err(_) if value.contains('+') => {
+            _ if value.contains('+') => {
                 anyhow::bail!("unexpected build field, expected a version like \"1.32\"")
             }
-            Err(_) if value.contains('-') => {
+            _ if value.contains('-') => {
                 anyhow::bail!("unexpected prerelease field, expected a version like \"1.32\"")
             }
             _ => anyhow::bail!("expected a version like \"1.32\""),

tests/testsuite/rust_version.rs

@@ -85,7 +85,7 @@ Caused by:
     |
   6 |             rust-version = \"1.43.0-beta.1\"
     |                            ^^^^^^^^^^^^^^^
-  expected a version like \"1.32\"",
+  unexpected prerelease field, expected a version like \"1.32\"",
         )
         .run();
 }