Provide more helpful error messages (e.g. line number) for parse failures

[stewartadam]

Some of the error messages don't provide any line numbers of the originating struct name, making them annoying to pin down:

Parsing error: "failed to parse a rust type: Tuples are not allowed in typeshare types" in file "../../git/project/src/outbound.rs"

Parsing error: "failed to parse a rust type: ["u64"]" in file "../../git/project/src/command_types.rs"

Would be nice to provide more helpful error messages that include the struct/enum name, like some of them do:

Parsing error: "serde tag attribute needs to be specified for algebraic enum Attribute. e.g. #[serde(tag = "type", content = "content")]" in file "../../git/project/src/attributes.rs"

[stewartadam]

Similarly, when a type parse failure occurs from a #[typeshare(serialized_as = "...")] the error is opaque and doesn't reference the type that failed to parse:

Parsing error: "failed to parse a rust type: []" in file "crates/src/outbound.rs"

[darrell-roberts]

This can be done. We probably should have been using Span since this already has all the parsing meta-data (Filename, line and column numbers) for error messaging. Would require a bit of reworking our error types and creating spans when creating errors. I'll take a look into it.

[darrell-roberts]

Created an MR that adds line and column number reporting to parser failure/rejections.

Example test invalid type parse error:

cat /tmp/typeshare-test/src/test.rs
//! This is a module comment

#[typeshare]
pub struct MyType {
    pub field: usize
}

Running from the command line.

cargo run --bin typeshare -- -l typescript -d /tmp/out /tmp/typeshare-test
   Compiling typeshare-core v1.13.3 (/home/droberts/projects/typeshare/core)
   Compiling typeshare-cli v1.13.3 (/home/droberts/projects/typeshare/cli)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.84s
     Running `target/debug/typeshare -l typescript -d /tmp/out /tmp/typeshare-test`
[2025-08-02 17:25:09.911115 -04:00] INFO [cli/src/main.rs:78] typeshare started generating types
[2025-08-02 17:25:09.911217 -04:00] INFO [cli/src/main.rs:85] Using directories: ["/tmp/typeshare-test"]
[2025-08-02 17:25:09.918404 -04:00] ERROR [cli/src/main.rs:296] Parsing error: "Failed to parse a Rust type: Unsupported type: "usize", on line 5 and column 15" in file "/tmp/typeshare-test/src/test.rs"
[2025-08-02 17:25:09.918466 -04:00] ERROR [cli/src/main.rs:304] Errors encountered during parsing.
[2025-08-02 17:25:09.918505 -04:00] ERROR [cli/src/main.rs:72] typeshare failed to generate types: Errors encountered during parsing.
Error: Errors encountered during parsing.

Notable parse error with file, line and column number:

Parsing error: "Failed to parse a Rust type: Unsupported type: "usize", on line 5 and column 15" in file "/tmp/typeshare-test/src/test.rs"

[stewartadam]

This looks great! Thank you