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lint get vs index dissonance #1314

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oli-obk opened this issue Nov 1, 2016 · 4 comments
Open

lint get vs index dissonance #1314

oli-obk opened this issue Nov 1, 2016 · 4 comments
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A-lint Area: New lints E-hard Call for participation: This a hard problem and requires more experience or effort to work on L-correctness Lint: Belongs in the correctness lint group L-style Lint: Belongs in the style lint group T-middle Type: Probably requires verifiying types

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@oli-obk
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oli-obk commented Nov 1, 2016

for custom types we aren't sure that .get().unwrap() and [] are actually equivalent. They probably should be, so let's lint them.

Idea by @devonhollowood in https://github.com/Manishearth/rust-clippy/pull/1312#issuecomment-257664178
@oli-obk oli-obk added E-medium Call for participation: Medium difficulty level problem and requires some initial experience. T-middle Type: Probably requires verifiying types A-lint Area: New lints L-style Lint: Belongs in the style lint group L-correctness Lint: Belongs in the correctness lint group labels Nov 1, 2016
@mcarton
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mcarton commented Nov 2, 2016

Oo how do you check that?
We're far from being able to prove code equivalence.

@mcarton mcarton added E-hard Call for participation: This a hard problem and requires more experience or effort to work on and removed E-medium Call for participation: Medium difficulty level problem and requires some initial experience. labels Nov 2, 2016
@oli-obk
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oli-obk commented Nov 2, 2016

well... one of them should probably forward to the other? xD

we can also compare fully inlined MIR or something

@mcarton
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mcarton commented Nov 2, 2016

It's not the case for example for Vec. Also for Vec, Index is also implemented on ranges, but get only works on indexes.

@oli-obk
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oli-obk commented Nov 2, 2016

Well... dissonance requires that both exist. So we'd only check those cases where the Index<T, Output=U> and the get(T) -> Option<U> exist as a pair.

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A-lint Area: New lints E-hard Call for participation: This a hard problem and requires more experience or effort to work on L-correctness Lint: Belongs in the correctness lint group L-style Lint: Belongs in the style lint group T-middle Type: Probably requires verifiying types
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