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libproc_macro calls are extremely expensive #134

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dtolnay opened this issue Oct 4, 2019 · 1 comment

Owner

dtolnay commented Oct 4, 2019

Context: rust-lang/rust#65080

We should look into anything quote can do to reduce number of proc_macro calls.

For example, something like

- tokens.extend(once(TokenTree::Punct(Punct::new(...))));
- tokens.extend(once(TokenTree::Punct(Punct::new(...))));
- tokens.extend(once(TokenTree::Punct(Punct::new(...))));
+ tokens.extend(vec![
+     TokenTree::Punct(Punct::new(...)),
+     TokenTree::Punct(Punct::new(...)),
+     TokenTree::Punct(Punct::new(...)),
+ ]);

could be a big improvement to compile times downstream by reducing TokenStream::extend calls.

Owner Author

dtolnay commented Oct 4, 2019

Closing in favor of dtolnay/proc-macro2#199 since this can be fixed in proc-macro2.

dtolnay closed this as completed

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