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Example code of Result.expect() confused me #2918

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shifujun opened this issue Nov 5, 2021 · 1 comment · Fixed by rust-lang/rust#97891
Closed
2 tasks done

Example code of Result.expect() confused me #2918

shifujun opened this issue Nov 5, 2021 · 1 comment · Fixed by rust-lang/rust#97891
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@shifujun
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shifujun commented Nov 5, 2021

  • I have checked the latest main branch to see if this has already been fixed
  • I have searched existing issues and pull requests for duplicates

URL to the section(s) of the book with this problem:

let f = File::open("hello.txt").expect("Failed to open hello.txt");

Description of the problem:

let f = File::open("hello.txt").expect("Failed to open hello.txt");

"expect failed to open hello.txt" confused me. Are we expecting a failure?

Suggested fix:

let f = File::open("hello.txt").expect("Succeed to open hello.txt");

Or explain this API design more.

Same confused from stackoverflow: https://stackoverflow.com/questions/66362625/why-is-rusts-expect-called-expect

@carols10cents carols10cents added this to the ch9 milestone Nov 7, 2021
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This RFC is related: rust-lang/rfcs#3218

carols10cents added a commit that referenced this issue Jun 4, 2022
- Change the variable name from filename to file_path. Fixes #3142.
- Use the new println capture. Connects to #3048.
- Use dbg! when appropriate. Connects to #2842.
- Improve the expect message to read better. Connects to #2918.
carols10cents added a commit that referenced this issue Jun 4, 2022
- Change the variable name from filename to file_path. Fixes #3142.
- Use the new println capture. Connects to #3048.
- Use dbg! when appropriate. Connects to #2842.
- Improve the expect message to read better. Connects to #2918.
compiler-errors added a commit to compiler-errors/rust that referenced this issue Jun 8, 2022
Update books

## nomicon

5 commits in 10d40c59a581c66d8ecd29ad18d410bf97ed524d..3a43983b76174342b7dbd3e12ea2c49f762e52be
2022-05-07 10:45:07 +0900 to 2022-05-30 17:01:30 +0900
- Changes for `c_unwind` (rust-lang/nomicon#365)
- Upgrade actions/checkout to v3 (rust-lang/nomicon#367)
- Clarification of borrowck (rust-lang/nomicon#354)
- Update the now stale warning about `PhantomData<T>` and dropck (rust-lang/nomicon#363)
- Minor language fixes (rust-lang/nomicon#364)

## reference

1 commits in b74825d8f88b685e239ade00f00de68ba4cd63d4..683bfe5cd64d589c6a1645312ab5f93b6385ccbb
2022-05-20 14:30:30 -0700 to 2022-05-27 11:54:20 -0700
- Reflect changes about unsizing casts in const context (rust-lang/reference#1221)

## book

58 commits in b4dd5f00b87190ad5ef42cbc2a88a783c6ae57ef..396fdb69de7fb18f24b15c7ad13491b1c1fa7231
2022-05-24 21:37:06 -0400 to 2022-06-08 10:02:35 -0400
- Make not-equals operator example consistent. Fixes rust-lang/book#3189.
- Propagate nostarch appendix edits to src
- Edits to edits to appendices
- Edits from nostarch for the appendices
- Propagate edits to chapter 20 to src
- Edits to edits of chapter 20
- Update reference to chapter 12 code that was changed
- Edits from nostarch to chapter 20
- Fix spelling mistake
- Propagate ch17 tech review changes to src
- Responses to tech review for ch17
- Chapter 17 tech review comments
- Update dependencies via `cargo update`
- Propagate changes from ch16 tech review to src
- Tech review comments and responses for chapter 16
- Println captures in chapter 15
- Propagate chapter 15 tech review edits to src
- Responses to tech review for chapter 15
- Tech review comments for chapter 15
- Merge branch 'ch14-tr'
- Upgrade to Rust 1.61
- Upgrade to Rust 1.60
- More little improvements to chapter 12
- Update references to ch12 to be Config::build instead of new
- Propagate ch12 tech review edits to src
- Responses to tech review of chapter 12
- Tech review comments of chapter 12
- Show directory layouts including integration test files
- Clarify that integration/doc tests aren't run if unit tests fail
- Propagate ch11 tech review edits to src
- Edits in response to tech review of chapter 11
- Comments from tech review in chapter 11
- Propagate other edits to nostarch
- Adjust listing so error output line numbers match
- Merge remote-tracking branch 'origin/pr/3153' into ch10-tr
- Reword a rewording about lifetimes of values vs references
- Merge remote-tracking branch 'origin/pr/3107' into ch10-tr
- Merge remote-tracking branch 'origin/pr/3104' into ch10-tr
- Propagate ch10 edits to src
- Edits in response to tech review
- Comments from tech review for chapter 10
- New dictionary entries
- Demonstrate a better expect message. Fixes rust-lang/book#2918.
- Propagate tech review ch9 edits to src
- Termination has stabilized! Fixes rust-lang/book#3116.
- Respond to tech review comments to chapter 9
- Comments from tech review on chapter 9
- Propagate changes for ch8 to src
- Clarify that split_whitespace returns an iterator
- Add type annotation in nostarch snapshot too
- Extra-clarity qualification
- Edits to chapter 8 in response to tech review
- Comments from tech review for chapter 8
- Propagate tech review edits to ch06 src
- Responses to tech review comments on chapter 6
- Chapter 6 after tech review
- Snapshot of chapter 1 for nostarch
- src: use TLSv1.3 if we're going to specify at all

## rust-by-example

4 commits in 2ed26865e8c29ef939dc913a97bd321cadd72a9a..dbb7e5e2345ee26199ffba218156b6009016a20c
2022-05-18 17:23:47 -0300 to 2022-06-02 16:30:51 -0300
- Fix typo in Traits → "impl Trait" (rust-lang/rust-by-example#1544)
- doc_testing.md: clarify tests vs doc-tests (rust-lang/rust-by-example#1547)
- unsafe::asm.md: add some explicit declarations (rust-lang/rust-by-example#1548)
- Update dsl.md to remove unnecessary braces (rust-lang/rust-by-example#1543)

## rustc-dev-guide

6 commits in 554c00e4805df7f7bffac7db408437d62d6dfb9a..6e4d6435db89bcc027b1bba9742e4f59666f5412
2022-05-24 17:15:35 -0700 to 2022-06-08 08:06:32 +0900
- Make build scripts and proc macros work with the suggested rust-analyzer config (rust-lang/rustc-dev-guide#1365)
- improve rustc_interface examples a little (rust-lang/rustc-dev-guide#1362)
- Bump regex from 1.4.3 to 1.5.5 in /ci/date-check (rust-lang/rustc-dev-guide#1364)
- Clarify cargo fallback behavior for rustup link (rust-lang/rustc-dev-guide#1273)
- Update rustc-driver related examples
- Triage some date references related to traits

## embedded-book

1 commits in f7cefbb995eec8c6148f213235e9e2e03268e775..cbb494f96da3268c2925bdadc65ca83d42f2d4ef
2022-04-20 10:38:51 +0000 to 2022-05-26 06:58:43 +0000
- Add Chinese translation repository  (rust-embedded/book#318)
matthiaskrgr added a commit to matthiaskrgr/rust that referenced this issue Jun 8, 2022
Update books

## nomicon

5 commits in 10d40c59a581c66d8ecd29ad18d410bf97ed524d..3a43983b76174342b7dbd3e12ea2c49f762e52be
2022-05-07 10:45:07 +0900 to 2022-05-30 17:01:30 +0900
- Changes for `c_unwind` (rust-lang/nomicon#365)
- Upgrade actions/checkout to v3 (rust-lang/nomicon#367)
- Clarification of borrowck (rust-lang/nomicon#354)
- Update the now stale warning about `PhantomData<T>` and dropck (rust-lang/nomicon#363)
- Minor language fixes (rust-lang/nomicon#364)

## reference

1 commits in b74825d8f88b685e239ade00f00de68ba4cd63d4..683bfe5cd64d589c6a1645312ab5f93b6385ccbb
2022-05-20 14:30:30 -0700 to 2022-05-27 11:54:20 -0700
- Reflect changes about unsizing casts in const context (rust-lang/reference#1221)

## book

58 commits in b4dd5f00b87190ad5ef42cbc2a88a783c6ae57ef..396fdb69de7fb18f24b15c7ad13491b1c1fa7231
2022-05-24 21:37:06 -0400 to 2022-06-08 10:02:35 -0400
- Make not-equals operator example consistent. Fixes rust-lang/book#3189.
- Propagate nostarch appendix edits to src
- Edits to edits to appendices
- Edits from nostarch for the appendices
- Propagate edits to chapter 20 to src
- Edits to edits of chapter 20
- Update reference to chapter 12 code that was changed
- Edits from nostarch to chapter 20
- Fix spelling mistake
- Propagate ch17 tech review changes to src
- Responses to tech review for ch17
- Chapter 17 tech review comments
- Update dependencies via `cargo update`
- Propagate changes from ch16 tech review to src
- Tech review comments and responses for chapter 16
- Println captures in chapter 15
- Propagate chapter 15 tech review edits to src
- Responses to tech review for chapter 15
- Tech review comments for chapter 15
- Merge branch 'ch14-tr'
- Upgrade to Rust 1.61
- Upgrade to Rust 1.60
- More little improvements to chapter 12
- Update references to ch12 to be Config::build instead of new
- Propagate ch12 tech review edits to src
- Responses to tech review of chapter 12
- Tech review comments of chapter 12
- Show directory layouts including integration test files
- Clarify that integration/doc tests aren't run if unit tests fail
- Propagate ch11 tech review edits to src
- Edits in response to tech review of chapter 11
- Comments from tech review in chapter 11
- Propagate other edits to nostarch
- Adjust listing so error output line numbers match
- Merge remote-tracking branch 'origin/pr/3153' into ch10-tr
- Reword a rewording about lifetimes of values vs references
- Merge remote-tracking branch 'origin/pr/3107' into ch10-tr
- Merge remote-tracking branch 'origin/pr/3104' into ch10-tr
- Propagate ch10 edits to src
- Edits in response to tech review
- Comments from tech review for chapter 10
- New dictionary entries
- Demonstrate a better expect message. Fixes rust-lang/book#2918.
- Propagate tech review ch9 edits to src
- Termination has stabilized! Fixes rust-lang/book#3116.
- Respond to tech review comments to chapter 9
- Comments from tech review on chapter 9
- Propagate changes for ch8 to src
- Clarify that split_whitespace returns an iterator
- Add type annotation in nostarch snapshot too
- Extra-clarity qualification
- Edits to chapter 8 in response to tech review
- Comments from tech review for chapter 8
- Propagate tech review edits to ch06 src
- Responses to tech review comments on chapter 6
- Chapter 6 after tech review
- Snapshot of chapter 1 for nostarch
- src: use TLSv1.3 if we're going to specify at all

## rust-by-example

4 commits in 2ed26865e8c29ef939dc913a97bd321cadd72a9a..dbb7e5e2345ee26199ffba218156b6009016a20c
2022-05-18 17:23:47 -0300 to 2022-06-02 16:30:51 -0300
- Fix typo in Traits → "impl Trait" (rust-lang/rust-by-example#1544)
- doc_testing.md: clarify tests vs doc-tests (rust-lang/rust-by-example#1547)
- unsafe::asm.md: add some explicit declarations (rust-lang/rust-by-example#1548)
- Update dsl.md to remove unnecessary braces (rust-lang/rust-by-example#1543)

## rustc-dev-guide

6 commits in 554c00e4805df7f7bffac7db408437d62d6dfb9a..6e4d6435db89bcc027b1bba9742e4f59666f5412
2022-05-24 17:15:35 -0700 to 2022-06-08 08:06:32 +0900
- Make build scripts and proc macros work with the suggested rust-analyzer config (rust-lang/rustc-dev-guide#1365)
- improve rustc_interface examples a little (rust-lang/rustc-dev-guide#1362)
- Bump regex from 1.4.3 to 1.5.5 in /ci/date-check (rust-lang/rustc-dev-guide#1364)
- Clarify cargo fallback behavior for rustup link (rust-lang/rustc-dev-guide#1273)
- Update rustc-driver related examples
- Triage some date references related to traits

## embedded-book

1 commits in f7cefbb995eec8c6148f213235e9e2e03268e775..cbb494f96da3268c2925bdadc65ca83d42f2d4ef
2022-04-20 10:38:51 +0000 to 2022-05-26 06:58:43 +0000
- Add Chinese translation repository  (rust-embedded/book#318)
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