new_syntax_error working without full compiler

Fix #4100

codegen/Cargo.toml

@@ -17,6 +17,7 @@ itertools = "0.10.3"
 log = "0.4.16"
 num-complex = { version = "0.4.0", features = ["serde"] }
 num-traits = "0.2.14"
+thiserror = "1.0"
 
 [dev-dependencies]
 rustpython-parser = { path = "../parser" }

codegen/src/error.rs

@@ -1,8 +1,8 @@
-use std::{error::Error, fmt};
+use std::fmt;
 
 pub type CodegenError = rustpython_compiler_core::BaseError<CodegenErrorType>;
 
-#[derive(Debug)]
+#[derive(Debug, thiserror::Error)]
 #[non_exhaustive]
 pub enum CodegenErrorType {
     /// Invalid assignment, cannot store value in target.
@@ -79,5 +79,3 @@ impl fmt::Display for CodegenErrorType {
         }
     }
 }
-
-impl Error for CodegenErrorType {}