rustc: Implement tokenization of nested items #52618
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Ever plagued by rust-lang#43081 the compiler can return surprising spans in situations related to procedural macros. This is exhibited by rust-lang#47983 where whenever a procedural macro is invoked in a nested item context it would fail to have correct span information. While rust-lang#43230 provided a "hack" to cache the token stream used for each item in the compiler it's not a full-blown solution. This commit continues to extend this "hack" a bit more to work for nested items. Previously in the parser the `parse_item` method would collect the tokens for an item into a cache on the item itself. It turned out, however, that nested items were parsed through the `parse_item_` method, so they didn't receive similar treatment. To remedy this situation the hook for collecting tokens was moved into `parse_item_` instead of `parse_item`. Afterwards the token collection scheme was updated to support nested collection of tokens. This is implemented by tracking `TokenStream` tokens instead of `TokenTree` to allow for collecting items into streams at intermediate layers and having them interleaved in the upper layers. All in all, this... Closes rust-lang#47983
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rustc: Implement tokenization of nested items Ever plagued by #43081 the compiler can return surprising spans in situations related to procedural macros. This is exhibited by #47983 where whenever a procedural macro is invoked in a nested item context it would fail to have correct span information. While #43230 provided a "hack" to cache the token stream used for each item in the compiler it's not a full-blown solution. This commit continues to extend this "hack" a bit more to work for nested items. Previously in the parser the `parse_item` method would collect the tokens for an item into a cache on the item itself. It turned out, however, that nested items were parsed through the `parse_item_` method, so they didn't receive similar treatment. To remedy this situation the hook for collecting tokens was moved into `parse_item_` instead of `parse_item`. Afterwards the token collection scheme was updated to support nested collection of tokens. This is implemented by tracking `TokenStream` tokens instead of `TokenTree` to allow for collecting items into streams at intermediate layers and having them interleaved in the upper layers. All in all, this... Closes #47983
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Ever plagued by #43081 the compiler can return surprising spans in situations
related to procedural macros. This is exhibited by #47983 where whenever a
procedural macro is invoked in a nested item context it would fail to have
correct span information.
While #43230 provided a "hack" to cache the token stream used for each item in
the compiler it's not a full-blown solution. This commit continues to extend
this "hack" a bit more to work for nested items.
Previously in the parser the
parse_itemmethod would collect the tokens for anitem into a cache on the item itself. It turned out, however, that nested items
were parsed through the
parse_item_method, so they didn't receive similartreatment. To remedy this situation the hook for collecting tokens was moved
into
parse_item_instead ofparse_item.Afterwards the token collection scheme was updated to support nested collection
of tokens. This is implemented by tracking
TokenStreamtokens instead ofTokenTreeto allow for collecting items into streams at intermediate layersand having them interleaved in the upper layers.
All in all, this...
Closes #47983