Fix hygene issue when deriving Debug #48934
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
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)].
|
( Closes #42453) |
|
uuuhhh... I guess highfive decided to ignore this. Maybe this will fix it? @rust-highfive |
|
r? @petrochenkov maybe |
|
@bors r+ rollup |
|
📌 Commit c033c6e has been approved by |
bors
added
the
S-waiting-on-bors
Mark-Simulacrum
added a commit
to Mark-Simulacrum/rust
that referenced
this pull request
Mar 12, 2018
…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
added a commit
to kennytm/rust
that referenced
this pull request
Mar 12, 2018
…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.
# for free
to join this conversation on GitHub.
Already have an account?
# to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
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.