Update nomicon for variance typo & contravariance #30332
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&'b mut B was described incorrectly (just in this example, is correct in the actual text).
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r? @brson (rust_highfive has picked a reviewer for you, use r? to override) |
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This updates nomicon to just mention contravariance without having a longer explanation. I will cast my own doubts on contravariance for fn() to be removed, since it will mean some valid trait implementations will stop compiling. It's a simple change for a parenthesis sentence, but I'll ping the language team anyway (sorry!) cc @rust-lang/lang |
| for functions. The future of contravariance is uncertain and it may be | ||
| scrapped. For now, `fn(T)` is contravariant in `T`, which is used in matching | ||
| methods in trait implementations to the trait definition. Traits are | ||
| not covariant in their parameters, so `Fn(T)`, is invariant in `T`). |
bluss
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@bors r+ rollup Needs work, but a clear improvement. |
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📌 Commit f9d029b has been approved by |
| for functions. The future of contravariance is uncertain and it may be | ||
| scrapped. For now, `fn(T)` is contravariant in `T`, which is used in matching | ||
| methods in trait implementations to the trait definition. Traits don't have | ||
| inferred variance, so `Fn(T)`, is invariant in `T`). |
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⌛ Testing commit f9d029b with merge 671afce... |
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💔 Test failed - auto-mac-64-opt |
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Fixed the comma, and let's see if bors can test this @bors r=gankro rollup |
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📌 Commit 2a30f0e has been approved by |
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⌛ Testing commit 2a30f0e with merge d538aa2... |
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💔 Test failed - auto-mac-64-opt |
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@bors: retry On Sat, Dec 12, 2015 at 12:19 AM, bors notifications@github.com wrote:
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Update nomicon for variance typo & contravariance
Fixes #28704
Fixes #28100