Remove 'unsafe' workarounds once pure goes away #4568
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C-cleanup
Category: PRs that clean code up or issues documenting cleanup.
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Apr 9, 2013
This removes some of the easier instances of mutable fields where the explicit self can just become `&mut self` along with removing some unsafe blocks which aren't necessary any more now that purity is gone. Most of #4568 is done, except for [one case](https://github.com/alexcrichton/rust/blob/less-mut-fields/src/libcore/vec.rs#L1754) where it looks like it has to do with it being a `const` vector. Removing the unsafe block yields: ``` /Users/alex/code/rust2/src/libcore/vec.rs:1755:12: 1755:16 error: illegal borrow unless pure: creating immutable alias to const vec content /Users/alex/code/rust2/src/libcore/vec.rs:1755 for self.each |e| { ^~~~ /Users/alex/code/rust2/src/libcore/vec.rs:1757:8: 1757:9 note: impure due to access to impure function /Users/alex/code/rust2/src/libcore/vec.rs:1757 } ^ error: aborting due to previous error ``` I also didn't delve too much into removing mutable fields with `Cell` or `transmute` and friends.
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Apr 15, 2013
Closes #5487, #1913, and #4568 I tracked this by adding all used unsafe blocks/functions to a set on the `tcx` passed around, and then when the lint pass comes around if an unsafe block/function isn't listed in that set, it's unused. I also removed everything from the compiler that was unused, and up to stage2 is now compiling without any known unused unsafe blocks. I chose `unused_unsafe` as the name of the lint attribute, but there may be a better name...
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Right now there are a lot of situations where you have to wrap the body of a function in an unsafe block to make it pure, because some of the functions you're using aren't declared as pure. Those have to be remove if purity goes away or its definition becomes broader.
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