rust/CHANGELOG.md

# Changelog

## [Unreleased]

## [1.4.22] 2020-10-04

### Changed

- Update `rustc-ap-*` crates to v679.0.0
- Add config option to allow control of leading match arm pipes
- Support `RUSTFMT` environment variable in `cargo fmt` to run specified `rustfmt` instance


### Fixed

- Fix preservation of type aliases within extern blocks


## [1.4.9] 2019-10-07

### Changed

- Update `rustc-ap-*` crates to 606.0.0.

### Fixed

- Fix aligning comments of different group
- Fix flattening imports with a single `self`.
- Fix removing attributes on function parameters.
- Fix removing `impl` keyword from opaque type. 

## [1.4.8] 2019-09-08

### Changed

- Update `rustc-ap-*` crates to 583.0.0.

## [1.4.7] 2019-09-06

### Added

- Add `--config` command line option.

### Changed

- Update `rustc-ap-*` crates to 581.0.0.
- rustfmt now do not warn against trailing whitespaces inside macro calls.

### Fixed

- Fix `merge_imports` generating invalid code.
- Fix removing discriminant values on enum variants.
- Fix modules defined inside `cfg_if!` not being formatted.
- Fix minor formatting issues.

## [1.4.6] 2019-08-28

### Added

- Add `--message-format` command line option to `cargo-fmt`.
- Add `-l,--files-with-diff` command line option to `rustfmt`.
- Add `json` emit mode. 

### Fixed

- Fix removing attributes on struct pattern's fields.
- Fix non-idempotent formatting of match arm.
- Fix `merge_imports` generating invalid code.
- Fix imports with `#![macro_use]` getting reordered with `reorder_imports`.
- Fix calculation of line numbers in checkstyle output.
- Fix poor formatting of complex fn type.

## [1.4.5] 2019-08-13

### Fixed

- Fix generating invalid code when formatting an impl block with const generics inside a where clause.
- Fix adding a trailing space after a `dyn` keyword which is used as a macro argument by itself.

## [1.4.4] 2019-08-06

### Fixed

- Fix `cargo fmt` incorrectly formatting crates that is not part of the workspace or the path dependencies.
- Fix removing a trailing comma from a tuple pattern.

## [1.4.3] 2019-08-02

### Changed

- Update `rustc-ap-*` crates to 546.0.0.

### Fixed

- Fix an underscore pattern getting removed.

## [1.4.2] 2019-07-31

### Changed

- Explicitly require the version of `rustfmt-config_proc_macro` to be 0.1.2 or later.

## [1.4.1] 2019-07-30

### Changed

- Update `rustc-ap-*` crates to 542.0.0.

## [1.4.0] 2019-07-29

### Added

- Add new attribute `rustfmt::skip::attributes` to prevent rustfmt 
from formatting an attribute #3665

### Changed

- Update `rustc-ap-*` crates to 541.0.0.
- Remove multiple semicolons.

## [1.3.3] 2019-07-15

### Added

- Add `--manifest-path` support to `cargo fmt` (#3683).

### Fixed

- Fix `cargo fmt -- --help` printing nothing (#3620).
- Fix inserting an extra comma (#3677).
- Fix incorrect handling of CRLF with `file-lines` (#3684).
- Fix `print-config=minimal` option (#3687).

## [1.3.2] 2019-07-06

### Fixed

- Fix rustfmt crashing when `await!` macro call is used in a method chain.
- Fix rustfmt not recognizing a package whose name differs from its directory's name.

## [1.3.1] 2019-06-30

### Added

- Implement the `Display` trait on the types of `Config`.

### Changed

- `ignore` configuration option now only supports paths separated by `/`. Windows-style paths are not supported.
- Running `cargo fmt` in a sub-directory of a project is now supported.

### Fixed

- Fix bugs that may cause rustfmt to crash.

## [1.3.0] 2019-06-09

### Added

- Format modules defined inside `cfg_if` macro calls #3600

### Changed

- Change option `format_doc_comment` to `format_code_in_doc_comment`.
- `use_small_heuristics` changed to be an enum and stabilised. Configuration
  options are now ready for 1.0.
- Stabilise `fn_args_density` configuration option and rename it to `fn_args_layout` #3581
- Update `rustc-ap-*` crates to 486.0.0
- Ignore sub-modules when skip-children is used #3607
- Removed bitrig support #3608

### Fixed

- `wrap_comments` should not imply `format_doc_comments` #3535
- Incorrect handling of const generics #3555
- Add the handling for `vec!` with paren inside macro #3576
- Format trait aliases with where clauses #3586
- Catch panics from the parser while rewriting macro calls #3589
- Fix erasing inner attributes in struct #3593
- Inline the attribute with its item even with the `macro_use` attribute or when `reorder_imports` is disabled #3598
- Fix the bug add unwanted code to impl #3602

## [1.2.2] 2019-04-24

### Fixed

- Fix processing of `ignore` paths #3522
- Attempt to format attributes if only they exist #3523

## [1.2.1] 2019-04-18

### Added

- Add `--print-config current` CLI option b473e65
- Create GitHub [page](https://rust-lang.github.io/rustfmt/) for Configuration.md #3485

### Fixed

- Keep comment appearing between parameter's name and its type #3491
- Do not delete semicolon after macro call with square brackets #3500
- Fix `--version` CLI option #3506
- Fix duplication of attributes on a match arm's body #3510
- Avoid overflowing item with attributes #3511

## [1.2.0] 2019-03-27

### Added

- Add new attribute `rustfmt::skip::macros` to prevent rustfmt from formatting a macro #3454

### Changed

- Discard error report in silent_emitter #3466

### Fixed

- Fix bad performance on deeply nested binary expressions #3467
- Use BTreeMap to guarantee consistent ordering b4d4b57

## [1.1.1] 2019-03-21

### Fixed

- Avoid panic on macro inside deeply nested block c9479de
- Fix line numbering in missed spans and handle file_lines in edge cases cdd08da
- Fix formatting of async blocks 1fa06ec
- Avoid duplication on the presence of spaces between macro name and `!` #3464

## [1.1.0] 2019-03-17

### Added

- Add `inline_attribute_width` configuration option to write an item and its attribute on the same line if their combined width is below a threshold #3409
- Support `const` generics f0c861b
- Support path clarity module #3448

### Changed

- Align loop and while formatting 7d9a2ef
- Support `EmitMode::ModifiedLines` with stdin input #3424
- Update `rustc-ap-*` crates to 407.0.0
- Remove trailing whitespaces in missing spans 2d5bc69

### Fixed

- Do not remove comment in the case of no arg 8e3ef3e
- Fix `Ident of macro+ident gets duplicated` error 40ff078
- Format the if expression at the end of the block in a single line 5f3dfe6

## [1.0.3] 2019-02-14

### Added

- Point unstable options to tracking issues 412dcc7

### Changed

- Update `rustc-ap-*` crates to 373.0.0

## [1.0.2] 2019-02-12

### Added

- Add a [section](https://github.com/rust-lang/rustfmt/blob/ae331be/Contributing.md#version-gate-formatting-changes) to the Contributing.md file about version-gating formatting changes 36e2cb0
- Allow specifying package with `-p` CLI option a8d2591
- Support `rustfmt::skip` on imports #3289
- Support global `rustfmt.toml` to be written in user config directory #3280
- Format visibility on trait alias 96a3df3

### Changed

- Do not modify original source code inside macro call #3260
- Recognize strings inside comments in order to avoid indenting them baa62c6
- Use Unicode-standard char width to wrap comments or strings a01990c
- Change new line point in the case of no args #3294
- Use the same formatting rule between functions and macros #3298
- Update rustc-ap-rustc_target to 366.0.0, rustc-ap-syntax to 366.0.0, and rustc-ap-syntax_pos to 366.0.0

### Fixed

- rewrite_comment: fix block fallback when failing to rewrite an itemized block ab7f4e1
- Catch possible tokenizer panics #3240
- Fix macro indentation on Windows #3266
- Fix shape when formatting return or break expr on statement position #3259
- rewrite_comment: fix block fallback when failing to rewrite an itemized block
- Keep leading double-colon to respect the 2018 edition of rust's paths a2bfc02
- Fix glob and nested global imports 2125ad2
- Do not force trailing comma when using mixed layout #3306
- Prioritize `single_line_fn` and `empty_item_single_line` over `brace_style` #3308
- Fix `internal error: left behind trailing whitespace` with long lines c2534f5
- Fix attribute duplication #3325
- Fix formatting of strings within a macro 813aa79
- Handle a macro argument with a single keyword 9a7ea6a

## [1.0.1] 2018-12-09

### Added

- Add a `version` option 378994b

### Changed

- End expressions like return/continue/break with a semicolon #3223
- Update rustc-ap-rustc_target to 306.0.0, rustc-ap-syntax to 306.0.0, and rustc-ap-syntax_pos to 306.0.0

### Fixed

- Allow to run a rustfmt command from cargo-fmt even when there is no target a2da636
- Fix `un-closed delimiter` errors when formatting break labels 40174e9

## [1.0.0] 2018-11-19

### Changed

- Preserve possibly one whitespace for brace macros 1a3bc79
- Prefer to break arguments over putting output type on the next line 1dd54e6

## [0.99.9] 2018-11-15

### Changed

- Update rustc-ap-rustc_target to 297.0.0, rustc-ap-syntax to 297.0.0, to rustc-ap-syntax_pos to 297.0.0
- Don't align comments on `extern crate`s dd7add7

## [0.99.8] 2018-11-14

### Added

- Add `overflow_delimited_expr` config option to more aggressively allow overflow #3175

### Fixed

- Fix the logic for retaining a comment before the arrow in a match #3181
- Do not wrap comments in doctest to avoid failing doctest runs #3183
- Fix comment rewriting that was wrapping code into a line comment #3188
- Fix formatting of unit-struct with `where`-clause #3200

## [0.99.7] 2018-11-07

### Changed

- Force a newline after the `if` condition if there is a different indentation level #3109
- Use correct width when formatting type on local statement #3126
- Treat crates non-alphabetically when ordering 799005f
- Fix formatting of code that is annotated with rustfmt::skip #3113
- Stabilize `edition` configuration option 9c3ae2d
- cargo-fmt: detect Rust edition in use #3129
- Trim the indentation on macros which heuristically appear to use block-style indentation #3178

### Fixed

- Do not remove path disambiugator inside macro #3142
- Improve handling of Windows newlines #3141
- Fix alignment of a struct's fields (`struct_field_align_threshold` option) with the Visual `indent_style` #3165
- Fix a bug in formatting markdown lists within comments #3172

## [0.99.6] 2018-10-18

### Added

- Add `enum_discrim_align_threshold` option to vertically align enum discriminants cc22869
- Add `println!`-like heuristic to the `fail` attribute #3067
- Handle itemized items inside comments #3083
- Add `format_doc_comments` configuration option to control the formatting of code snippets inside comments #3089

### Changed

- Makes brace behavior consistent with empty bodies for traits and impls 2727d41
- Consider a multi-lined array as a block-like expression #3969
- Improve formatting of strings #3073
- Get rid of extra commas in Visual struct literal formatting #3077
- Update rustc-ap-rustc_target to 274.0.0, rustc-ap-syntax to 274.0.0, and rustc-ap-syntax_pos to 274.0.0
- Format macro calls with item-like arguments #3080
- Avoid control flow expressions conditions to go multi line ef59b34
- Simplify multi-lining binop expressions #3101

### Fixed

- Do not format a code block in documentation if it is annotated with ignore or text 2bcc3a9
- Fix inconsistent overflow behavior in Visual style #3078
- Fix corner cases of the string formatting implementation #3083
- Do not add parens around lifetimes 0ac68c9
- Catch parser panic in format_snippet 8c4e92a

## [0.99.5] 2018-09-25

### Added

- Handle leading module separator for 2018 Edition #2952
- Add configuration option `normalize_doc_attributes`: convert doc attributes to comments #3002

### Changed

- Accept 2015 and 2018 instead of Edition2015 and Edition2018 for edition option eec7436
- Support platforms without a timer 46e2a2e
- Update rustc-ap-rustc_target to 263.0.0, rustc-ap-syntax to 263.0.0, and rustc-ap-syntax_pos to 263.0.0

### Fixed

- Format of attributes with commas #2971
- Fix optional arg condensing #2972
- Improve formatting of long function parameters #2981
- Fix formatting of raw string literals #2983
- Handle chain with try operators with spaces #2986
- Use correct shape in Visual tuple rewriting #2987
- Impove formatting of arguments with `visual_style = "Visual"` option #2988
- Change `print_diff` to output the correct line number 992b179
- Propagate errors about failing to rewrite a macro 6f318e3
- Handle formatting of long function signature #3010
- Fix indent computation of a macro with braces c3edf6d
- Format generics on associated types #3035
- Incorrect indentation of multiline block match expression #3042
- Fix bug in import where two consecutive module separators were possible 98a0ef2
- Prevent right-shifting of block comments with bare lines 5fdb6db

## [0.99.4] 2018-08-27

### Added

- Handle formatting of underscore imports #2951
- Handle formatting of try blocks #2965

### Changed

- Update rustc-ap-rustc_target to 237.0.0, rustc-ap-syntax to 237.0.0, and rustc-ap-syntax_pos to 237.0.0 ca19c9a
- Consider `dev` channel as nightly for unstable features #2948

### Fixed

- Fix formatting of patterns with ellipsis # 2942

## [0.99.3] 2018-08-23

### Added

- Use path attribute when searching for modules #2901
- Expose FileLines JSON representation to allow external libraries to use the file_lines option #2915

### Changed

- Replace '--conifig-help' with '--config=help' cb10e06
- Improve formatting of slice patterns #2912

### Fixed

- Format chains with comment #2899
- Fix indentation of formatted macro body #2920
- Fix indentation of block comments f23e6aa

## [0.99.2] 2018-08-07

### Changed

- Update rustc-ap-rustc_target to 218.0.0, rustc-ap-syntax to 218.0.0, and rustc-ap-syntax_pos to 218.0.0 5c9a2b6
- Combine function-like attributes #2900

### Fixed

- Explicitly handle semicolon after the item in statement position d96e3ca
- Fix parsing '#'-hiding of rustdoc 2eca09e

## [0.99.1] 2018-08-04

### Fixed

- fix use statements ordering when a number is present 1928ae7

## [0.99.0] 2018-08-03

- 1.0 RC release

### Changed

- Clarification in README.md 30fe66b

## [0.9.0] 2018-08-01

### Added

- Handle raw identifiers 3027c21
- Format async closure 60ce411
- Add max_width option for all heuristics c2ae39e
- Add config option `format_macro_matchers` to format the metavariable matching patterns in macros 79c5ee8
- Add config option `format_macro_bodies` to format the bodies of macros 79c5ee8
- Format exitential type fc307ff
- Support raw identifiers in struct expressions f121b1a
- Format Async block and async function 0b25f60

### Changed

- Update rustc-ap-rustc_target to 211.0.0, rustc-ap-syntax to 211.0.0, and rustc-ap-syntax_pos to 211.0.0
- Put each nested import on its own line while putting non-nested imports on the same line as much as possible 42ab258
- Respect `empty_item_single_line` config option when formatting empty impls. Put the `where` on its own line to improve readability #2771
- Strip leading `|` in match arm patterns 1d4b988
- Apply short function call heuristic to attributes 3abebf9
- Indent a match guard if the pattern is multiline be4d37d
- Change default newline style to `Native` 9d8f381
- Improve formatting of series of binop expressions a4cdb68
- Trigger an internal error if we skip formatting due to a lost comment b085113
- Refactor chain formatting #2838

### Fixed

- Do not insert spaces around braces with empty body or multiple lines 2f65852
- Allow using mixed layout with comments #2766
- Handle break labels #2726
- fix rewrite_string when a line feed is present 472a2ed
- Fix an anomaly with comments and array literals b28a0cd
- Check for comments after the `=>` in a match arm 6899471

## [0.8.0,0.8.1,0.8.2] 2018-05-28

### Added

- Use scoped attributes for skip attribute https://github.com/rust-lang/rustfmt/pull/2703

### Changed

- Comment options `wrap_comments` and `normalize_comments` are reverted back to unstable 416bc4c
- Stabilise `reorder_imports` and `reorder_modules` options 7b6d2b4
- Remove `spaces_within_parens_and_brackets` option d726492
- Stabilise shorthand options: `use_try_shorthand`, `use_field_init_shorthand`, and `force_explicit_abi` 8afe367
- Stabilise `remove_nested_parens` and set default to true a70f716
- Unstabilise `unstable_features` dd9c15a
- Remove `remove_blank_lines_at_start_or_end_of_block` option 2ee8b0e
- Update rustc-ap-syntax to 146.0.0 and rustc-ap-rustc_target to 146.0.0 2c275a2
- Audit the public API #2639

### Fixed

- Handle code block in doc comment without rust prefix f1974e2

## [0.7.0] 2018-05-14

### Added

- Add integration tests against crates in the rust-lang-nursery c79f39a

### Changed

- Update rustc-ap-syntax to 128.0.0 and ustc-ap-rustc_target to 128.0.0 195395f
- Put operands on its own line when each fits in a single line f8439ce
- Improve CLI options 55ac062 1869888 798bffb 4d9de48 eca7796 8396da1 5d9f5aa

### Fixed

- Use correct line width for list attribute 61a401a
- Avoid flip-flopping impl items when reordering them 37c216c
- Formatting breaks short lines when max_width is less than 100 9b36156
- Fix variant "Mixed" of imports_layout option 8c8676c
- Improve handling of long lines f885039
- Fix up lines exceeding max width 51c07f4
- Fix handling of modules in non_modrs_mods style cf573e8
- Do not duplicate attributes on use items e59ceaf
- Do not insert an extra brace in macros with native newlines 4c9ef93

## [0.6.1] 2018-05-01

### Changed

- Change the default value of imports_indent to IndentStyle::Block https://github.com/rust-lang/rustfmt/pull/2662

### Fixed

- Handle formatting of auto traits 5b5a72c
- Use consistent formatting for empty enum and struct https://github.com/rust-lang/rustfmt/pull/2656

## [0.6.0] 2018-04-20

### Changed

- Improve public API 8669004

## [0.5.0] 2018-04-20

### Added

- Add `verbose-diff` CLI option 5194984

### Changed

- Update rustc-ap-syntax to 103.0.0 dd807e2
- Refactor to make a sensible public API ca610d3

### Fixed

- Add spaces between consecutive `..` `..=` 61d29eb

## [0.4.2] 2018-04-12

### Added

- Handle binary operators and lifetimes 0fd174d
- Add reorder_impl_items config option 94f5a05
- Add `--unstable-features` CLI option to list unstable options from the `--help` output 8208f8a
- Add merge_imports config option 5dd203e

### Changed

- Format macro arguments with vertical layout ec71459
- Reorder imports by default 164cf7d
- Do not collapse block around expr with condition on match arm 5b9b7d5
- Use vertical layout for complex attributes c77708f
- Format array using heuristics for function calls 98c6f7b
- Implement stable ordering for impl items with the the following item priority: type, const, macro, then method fa80ddf
- Reorder imports by default 164cf7d
- Group `extern crate` by default 3a138a2
- Make `error_on_line_overflow` false by default f146711
- Merge imports with the same prefix into a single nested import 1954513
- Squash the various 'reorder imports' option into one 911395a

### Fixed

- Print version is missing the channel ca6fc67
- Do not add the beginning vert to the match arm 1e1d9d4
- Follow indent style config when formatting attributes efd295a
- Do not insert newline when item is empty a8022f3
- Do not indent or unindent inside string literal ec1907b

## [0.4.1] 2018-03-16

### Added

- Add `ignore` configuration option.
- Add `license_template_path` configuration option.
- Format `lazy_static!`.

### Fixed

- Fix formatting bugs.
- Fix setting `reorder_modules` removing inline modules.
- Format attributes on block expressions.
- Support `dyn trait` syntax.
- Support multiple patterns in `if let` and `while let`.
- Support a pattern with parentheses.

## [0.4.0] 2018-03-02

### Changed

- Do not print verbose outputs when formatting with stdin.
- Preserve trailing whitespaces in doc comments.
- Scale the values of width heuristics by `max_width`.

### Fixed

- Do not reorder items with `#[macro_use]`.
- Fix formatting bugs.
- Support the beginning `|` on a match arm.

## [0.3.8] 2018-02-04

### Added

- Format (or at least try to format) `macro_rules!`.

## [0.3.7] 2018-02-01

### Added

- Add `use_field_init_shorthand` config option.
- Add `reorder_modules` configuration option.

## [0.3.6] 2018-01-18

### Fixed

- Fix panicking on formatting certain macros (#2371).

## [0.3.5] 2018-01-15

### Changed

- Format code block in comments when `wrap_comments` is set to `true`.
- Remove `same_line_attributes` configuration option.
- Rename `git-fmt` to `git-rustfmt`.

### Fixed

- Rustup to `rustc 1.25.0-nightly (e6072a7b3 2018-01-13)`.
- Fix formatting bugs.

## [0.3.4] 2017-12-23

### Added

- Add `--version` flag to `cargo-fmt`, allow `cargo fmt --version`.

### Fixed

- Rustup to `rustc 1.24.0-nightly (5165ee9e2 2017-12-22)`.

## [0.3.3] 2017-12-22

### Added

- Format trait aliases.

### Changed

- `cargo fmt` will format every workspace member.

### Fixed

- Rustup to `rustc 1.24.0-nightly (250b49205 2017-12-21)`
- Fix formatting bugs.

## [0.3.2] 2017-12-15

### Changed

- Warn when unknown configuration option is used.

### Fixed

- Rustup to `rustc 1.24.0-nightly (0077d128d 2017-12-14)`.

## [0.3.1] 2017-12-11

### Added

- Add `error_on_unformatted` configuration option.
- Add `--error-on-unformatted` command line option.

### Changed

- Do not report formatting errors on comments or strings by default.
- Rename `error_on_line_overflow_comments` to `error_on_unformatted`.

### Fixed

- Fix formatting bugs.
- Fix adding a trailing whitespace inside code block when `wrap_comments = true`.

## [0.3.0] 2017-12-11

### Added

- Support nested imports.

### Changed

- Do not report errors on skipped items.
- Do not format code block inside comments when `wrap_comments = true`.
- Keep vertical spaces between items within range.
- Format `format!` and its variants using compressed style.
- Format `write!` and its variants using compressed style.
- Format **simple** array using compressed style.

### Fixed

- Fix `rustfmt --package package_name` not working properly.
- Fix formatting bugs.

## [0.2.17] 2017-12-03

### Added

- Add `blank_lines_lower_bound` and `blank_lines_upper_bound` configuration options.

### Changed

- Combine configuration options related to width heuristic into `width_heuristic`.
- If the match arm's body is `if` expression, force to use block.

### Fixed

- Fix `cargo fmt --all` being trapped in an infinite loop.
- Fix many formatting bugs.

### Removed

- Remove legacy configuration options.

## [0.2.16] 2017-11-21

### Added

- Remove empty lines at the beginning of the file.
- Soft wrapping on doc comments.

### Changed

- Break before `|` when using multiple lines for match arm patterns.
- Combine `control_style`, `where_style` and `*_indent` config options into `indent_style`.
- Combine `item_brace_style` and `fn_brace_style` config options into `brace_style`.
- Combine config options related spacing around colons into `space_before_colon` and `space_after_colon`.

### Fixed

- Fix many bugs.

## [0.2.15] 2017-11-08

### Added

- Add git-fmt tool
- `where_single_line` configuration option.

### Changed

- Rename `chain_one_line_max` to `chain_width`.
- Change the suffix of indent-related configuration options to `_indent`.

## [0.2.14] 2017-11-06

### Fixed

- Rustup to the latest nightly.

## [0.2.13] 2017-10-30

### Fixed

- Rustup to the latest nightly.

## [0.2.12] 2017-10-29

### Fixed

- Fix a bug that `cargo fmt` hangs forever.

## [0.2.11] 2017-10-29

### Fixed

- Fix a bug that `cargo fmt` crashes.

## [0.2.10] 2017-10-28

## [0.2.9] 2017-10-16

## [0.2.8] 2017-09-28

## [0.2.7] 2017-09-21

### Added

- `binop_separator` configuration option (#1964).

### Changed

- Use horizontal layout for function call with a single argument.

### Fixed

- Fix panicking when calling `cargo fmt --all` (#1963).
- Refactorings & faster rustfmt.

## [0.2.6] 2017-09-14

### Fixed

- Fix a performance issue with nested block (#1940).
- Refactorings & faster rustfmt.

## [0.2.5] 2017-08-31

### Added

- Format and preserve attributes on statements (#1933).

### Fixed

- Use getters to access `Span` fields (#1899).

## [0.2.4] 2017-08-30

### Added

- Add support for `Yield` (#1928).

## [0.2.3] 2017-08-30

### Added

- `multiline_closure_forces_block` configuration option (#1898).
- `multiline_match_arm_forces_block` configuration option (#1898).
- `merge_derives` configuration option (#1910).
- `struct_remove_empty_braces` configuration option (#1930).
- Various refactorings.

### Changed

- Put single-lined block comments on the same line with list-like structure's item (#1923).
- Preserve blank line between doc comment and attribute (#1925).
- Put the opening and the closing braces of enum and struct on the same line, even when `item_brace_style = "AlwaysNextLine"` (#1930).

### Fixed

- Format attributes on `ast::ForeignItem` and take max width into account (#1916).
- Ignore empty lines when calculating the shortest indent width inside macro with braces (#1918).
- Handle tabs properly inside macro with braces (#1918).
- Fix a typo in `compute_budgets_for_args()` (#1924).
- Recover comment between keyword (`impl` and `trait`) and `{` which used to get removed (#1925).