proc_macro: Stay on the "use the cache" path more #50069
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Discovered in rust-lang#50061 we're falling off the "happy path" of using a stringified token stream more often than we should. This was due to the fact that a user-written token like `0xf` is equality-different from the stringified token of `15` (despite being semantically equivalent). This patch updates the call to `eq_unspanned` with an even more awful solution, `probably_equal_for_proc_macro`, which ignores the value of each token and basically only compares the structure of the token stream, assuming that the AST doesn't change just one token at a time. While this is a step towards fixing rust-lang#50061 there is still one regression from rust-lang#49154 which needs to be fixed.
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r? @nrc |
pietroalbini
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Oh my. @bors: r+ (but I hope you feel bad about this :-) ) |
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📌 Commit e934873 has been approved by |
bors
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I do feel bad :( This is indeed casting a shadow of a doubt on macros 1.2... |
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Apr 20, 2018
proc_macro: Stay on the "use the cache" path more Discovered in #50061 we're falling off the "happy path" of using a stringified token stream more often than we should. This was due to the fact that a user-written token like `0xf` is equality-different from the stringified token of `15` (despite being semantically equivalent). This patch updates the call to `eq_unspanned` with an even more awful solution, `probably_equal_for_proc_macro`, which ignores the value of each token and basically only compares the structure of the token stream, assuming that the AST doesn't change just one token at a time. While this is a step towards fixing #50061 there is still one regression from #49154 which needs to be fixed.
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☀️ Test successful - status-appveyor, status-travis |
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Discovered in #50061 we're falling off the "happy path" of using a stringified
token stream more often than we should. This was due to the fact that a
user-written token like
0xfis equality-different from the stringified tokenof
15(despite being semantically equivalent).This patch updates the call to
eq_unspannedwith an even more awful solution,probably_equal_for_proc_macro, which ignores the value of each token andbasically only compares the structure of the token stream, assuming that the AST
doesn't change just one token at a time.
While this is a step towards fixing #50061 there is still one regression
from #49154 which needs to be fixed.