Make Result::{and, and_then} generic over error types implementing FromError
#19078
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…FromError This change may result in additional type annotations being required when using those two methods, in particular when the error type of the Result argument is not known. [breaking-change]
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cc @aturon |
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So, one question about this overall approach: it seems to assume that the first error in the chain is at a "lower level" of abstraction than the second (if you think of In particular, for the I'm curious whether you've thought about supporting this more general use case? It seems like it would complicate the signatures significantly, and possibly hurt type inference more, but I'd still like to see what it looks like. |
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Closing out of inactivity (and to help clear out @bors's queue), but feel free to reopen with a rebase! |
alexcrichton
added a commit
to alexcrichton/rust
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Dec 17, 2014
This commit, like the second pass of `Option`, largely just stablizes the
existing functionality after renaming a few iterators.
The specific actions taken were:
* The `Ok` and `Err` variants were marked `#[stable]` as the stability
inheritance was since removed.
* The `as_mut` method is now stable.
* The `map` method is now stable
* The `map_err` method is now stable
* The `iter`, `iter_mut`, and `into_iter` methods now returned structures named
after the method of iteration. The methods are also now all stable.
* The `and_then` method is now stable.
* The `or_else` method is now stable.
* The `unwrap` family of functions are now all stable: `unwrap_or`,
`unwrap_or_else`, `unwrap`, and `unwrap_err`.
There is a possible open extension to `Result::{and, and_then}` to make the
return type further generic over `FromError` (as proposed in rust-lang#19078), but this
is a backwards compatible change due to the usage of default type parameters,
which makes the two functions safe to stabilize now regardless of the outcome of
that issue.
alexcrichton
added a commit
to alexcrichton/rust
that referenced
this pull request
Dec 19, 2014
This commit, like the second pass of `Option`, largely just stablizes the
existing functionality after renaming a few iterators.
The specific actions taken were:
* The `Ok` and `Err` variants were marked `#[stable]` as the stability
inheritance was since removed.
* The `as_mut` method is now stable.
* The `map` method is now stable
* The `map_err` method is now stable
* The `iter`, `iter_mut`, and `into_iter` methods now returned structures named
after the method of iteration. The methods are also now all stable.
* The `and_then` method is now stable.
* The `or_else` method is now stable.
* The `unwrap` family of functions are now all stable: `unwrap_or`,
`unwrap_or_else`, `unwrap`, and `unwrap_err`.
There is a possible open extension to `Result::{and, and_then}` to make the
return type further generic over `FromError` (as proposed in rust-lang#19078), but this
is a backwards compatible change due to the usage of default type parameters,
which makes the two functions safe to stabilize now regardless of the outcome of
that issue.
bors
added a commit
that referenced
this pull request
Dec 21, 2014
This commit, like the second pass of `Option`, largely just stablizes the
existing functionality after renaming a few iterators.
The specific actions taken were:
* The `Ok` and `Err` variants were marked `#[stable]` as the stability
inheritance was since removed.
* The `as_mut` method is now stable.
* The `map` method is now stable
* The `map_err` method is now stable
* The `iter`, `iter_mut`, and `into_iter` methods now returned structures named
after the method of iteration. The methods are also now all stable.
* The `and_then` method is now stable.
* The `or_else` method is now stable.
* The `unwrap` family of functions are now all stable: `unwrap_or`,
`unwrap_or_else`, `unwrap`, and `unwrap_err`.
There is a possible open extension to `Result::{and, and_then}` to make the
return type further generic over `FromError` (as proposed in #19078), but this
is a backwards compatible change due to the usage of default type parameters,
which makes the two functions safe to stabilize now regardless of the outcome of
that issue.
alexcrichton
added a commit
to alexcrichton/rust
that referenced
this pull request
Dec 21, 2014
This commit, like the second pass of `Option`, largely just stablizes the
existing functionality after renaming a few iterators.
The specific actions taken were:
* The `Ok` and `Err` variants were marked `#[stable]` as the stability
inheritance was since removed.
* The `as_mut` method is now stable.
* The `map` method is now stable
* The `map_err` method is now stable
* The `iter`, `iter_mut`, and `into_iter` methods now returned structures named
after the method of iteration. The methods are also now all stable.
* The `and_then` method is now stable.
* The `or_else` method is now stable.
* The `unwrap` family of functions are now all stable: `unwrap_or`,
`unwrap_or_else`, `unwrap`, and `unwrap_err`.
There is a possible open extension to `Result::{and, and_then}` to make the
return type further generic over `FromError` (as proposed in rust-lang#19078), but this
is a backwards compatible change due to the usage of default type parameters,
which makes the two functions safe to stabilize now regardless of the outcome of
that issue.
ghost
mentioned this pull request
lnicola
added a commit
to lnicola/rust
that referenced
this pull request
Feb 10, 2025
minor: Stop running some release workflows on forks and update old URLs
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This change may result in additional type annotations being required when
using those two methods, in particular when the error type of the Result argument
is not known.
[breaking-change]
Closes #18991.