When snapshoting a TokenCursor, preserve the top frame of the stack #81352
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If we start capturing on the first token of a frame,
we can legally pop the frame (e.g. we can capture something like
'{ my_tokens } other_tokens'. As a result, we need to snapshot the frame
at the top of the current stack, rather than just using an empty stack.
Fixes taiki-e/pin-project#312
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| // (e.g. the '{' in '{ my_tokens }'), then we can legally | ||
| // exit the frame (e.g. collecting '{ my_tokens } something_else' | ||
| // Therefore, we preserve the top of the stack, but nothing else | ||
| stack: self.token_cursor.stack.first().cloned().into_iter().collect(), |
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| stack: self.token_cursor.stack.first().cloned().into_iter().collect(), | |
| stack: if self.token_cursor.stack.is_empty() { vec![] } else { vec![TokenCursorFrame::dummy()] } |
I'm not actually sure, does it matter what exactly we put into the stack here, or putting any dummy frame making stack.pop() work without panic would be enough?
I'm asking because first() is not the top of the stack, it's the bottom, but things still seem to work.
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Oh, that's a good point. I'll need to take a closer look at how this is working.
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Closing in favor of #81472 |
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If we start capturing on the first token of a frame,
we can legally pop the frame (e.g. we can capture something like
'{ my_tokens } other_tokens'. As a result, we need to snapshot the frame
at the top of the current stack, rather than just using an empty stack.
Fixes taiki-e/pin-project#312