Use extend when creating the lint pass constructors (#15994)

Alternative to part of #14509. changelog: none

Author: blyxyas

clippy_dev/src/new_lint.rs

@@ -157,18 +157,19 @@ fn add_lint(lint: &LintData<'_>, enable_msrv: bool) -> io::Result<()> {
  let path = "clippy_lints/src/lib.rs";
  let mut lib_rs = fs::read_to_string(path).context("reading")?;
 
- let comment_start = lib_rs.find("// add lints here,").expect("Couldn't find comment");
- let ctor_arg = if lint.pass == Pass::Late { "_" } else { "" };
- let lint_pass = lint.pass;
+ let (comment, ctor_arg) = if lint.pass == Pass::Late {
+ ("// add late passes here", "_")
+ } else {
+ ("// add early passes here", "")
+ };
+ let comment_start = lib_rs.find(comment).expect("Couldn't find comment");
  let module_name = lint.name;
  let camel_name = to_camel_case(lint.name);
 
  let new_lint = if enable_msrv {
- format!(
- "store.register_{lint_pass}_pass(move |{ctor_arg}| Box::new({module_name}::{camel_name}::new(conf)));\n ",
- )
+ format!("Box::new(move |{ctor_arg}| Box::new({module_name}::{camel_name}::new(conf))),\n ",)
  } else {
- format!("store.register_{lint_pass}_pass(|{ctor_arg}| Box::new({module_name}::{camel_name}));\n ",)
+ format!("Box::new(|{ctor_arg}| Box::new({module_name}::{camel_name})),\n  ",)
  };
 
  lib_rs.insert_str(comment_start, &new_lint);