Fix hygene issue when deriving Debug #48934
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The code for several of the core traits doesn't use hygenic macros. This isn't a problem, except for the Debug trait, which is the only one that uses a variable, named "builder". Variables can't share names with unit structs, so attempting to [derive(Debug)] on any type while a unit struct with the name "builder" was in scope would result in an error. This commit just changes the name of the variable to "__debug_trait_builder", because I couldn't figure out how to get a list of all unit structs in-scope from within the derive expansion function. If someone wants to have a unit struct with the exact name "__debug_trait_builder", they'll just have to do it without a [derive(Debug)].
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( Closes #42453) |
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uuuhhh... I guess highfive decided to ignore this. Maybe this will fix it? @rust-highfive |
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r? @petrochenkov maybe |
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@bors r+ rollup |
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📌 Commit c033c6e has been approved by |
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Mark-Simulacrum
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…etrochenkov Fix hygene issue when deriving Debug The code for several of the core traits doesn't use hygenic macros. This isn't a problem, except for the Debug trait, which is the only one that uses a variable, named "builder". Variables can't share names with unit structs, so attempting to [derive(Debug)] on any type while a unit struct with the name "builder" was in scope would result in an error. This commit just changes the name of the variable to "__debug_trait_builder", because I couldn't figure out how to get a list of all unit structs in-scope from within the derive expansion function. If someone wants to have a unit struct with the exact name "__debug_trait_builder", they'll just have to do it without a [derive(Debug)]. I also checked the implementations of the other built-in derives to ensure they didn't declare any variables.
kennytm
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…etrochenkov Fix hygene issue when deriving Debug The code for several of the core traits doesn't use hygenic macros. This isn't a problem, except for the Debug trait, which is the only one that uses a variable, named "builder". Variables can't share names with unit structs, so attempting to [derive(Debug)] on any type while a unit struct with the name "builder" was in scope would result in an error. This commit just changes the name of the variable to "__debug_trait_builder", because I couldn't figure out how to get a list of all unit structs in-scope from within the derive expansion function. If someone wants to have a unit struct with the exact name "__debug_trait_builder", they'll just have to do it without a [derive(Debug)]. I also checked the implementations of the other built-in derives to ensure they didn't declare any variables.
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The code for several of the core traits doesn't use hygenic macros.
This isn't a problem, except for the Debug trait, which is the only
one that uses a variable, named "builder".
Variables can't share names with unit structs, so attempting to
[derive(Debug)] on any type while a unit struct with the name
"builder" was in scope would result in an error.
This commit just changes the name of the variable to
"__debug_trait_builder", because I couldn't figure out how to get a
list of all unit structs in-scope from within the derive expansion
function. If someone wants to have a unit struct with
the exact name "__debug_trait_builder", they'll just have to do it
without a [derive(Debug)].
I also checked the implementations of the other built-in derives to
ensure they didn't declare any variables.