11.0.0-alpha.1

🚀 Main New Features

• Introduce experimental uncurried mode. For experimentation only. PR #5796
• Customization of runtime representation of variants and introduction of untagged variants PR #6095, PR #6103

🚀 New Feature

• Add support for uncurried mode: a mode where everything is considered uncurried, whether with or without the .. This can be turned on with @@uncurried locally in a file. For project-level configuration in bsconfig.json, there's a boolean config "uncurried", which propagates to dependencies, to turn on uncurried mode.
  Since there's no syntax for partial application in this new mode, introduce @res.partial foo(x) to express partial application. This is temporary and will later have some surface syntax.
  Make uncurried functions a subtype of curried functions, and allow application for uncurried functions.
  The make function of components is generated as an uncurried function.
  Use best effort to determine the config when formatting a file.
  #5968 #6080 #6086 #6087
• Customization of runtime representation of variants. This is work in progress. E.g. some restrictions on the input. See comments of the form "TODO: put restriction on the variant definitions allowed, to make sure this never happens". #6095
• Introduce untagged variants #6103
• Add support for unary uncurried pipe in uncurried mode #5804
• Add support for partial application of uncurried functions: with uncurried application one can provide a
  subset of the arguments, and return a curried type with the remaining ones #5805
• Add support for uncurried externals #5815 #5819 #5830 #5894
• Parser/Printer: unify uncurried functions of arity 0, and of arity 1 taking unit. There's now only arity 1 in the source language. #5825
• Add support for default arguments in uncurried functions #5835
• Inline uncurried application when it is safe #5847
• Support optional named arguments without a final unit in uncurried functions #5907
• GenType: add the option to use the @genType annotation at the module level, meaning that all the items in the module should be exported. #6113
• GenType: add support for @genType annotations on module definitions. #6113
• Prebuilt binaries are now provided for all major platforms:
  • macOS x64
  • macOS ARM
  • Linux x64 (statically linked)
  • Linux ARM (statically linked)
  • Windows x64

💥 Breaking Change

• Remove support for the legacy Reason syntax. Existing Reason code can be converted to ReScript syntax using ReScript 9 as follows:
  • npm i -g rescript@9
  • rescript convert <reason files>
• Remove obsolete built-in project templates and the "rescript init" functionality. This is replaced by create-rescript-app which is maintained separately.
• Do not attempt to build ReScript from source on npm postinstall for platforms without prebuilt binaries anymore.
• Made pinned dependencies transitive: if a is a pinned dependency of b and b is a pinned dependency of c, then a is implicitly a pinned dependency of c. This change is only breaking if your build process assumes non-transitivity.
• Curried after uncurried is not fused anymore: (. x) => y => 3 is not equivalent to (. x, y) => 3 anymore. It's instead equivalent to (. x) => { y => 3 }.
  Also, (. int) => string => bool is not equivalen to (. int, string) => bool anymore.
  These are only breaking changes for unformatted code.
• Exponentiation operator ** is now right-associative. 2. ** 3. ** 2. now compile to Math.pow(2, Math.pow(3, 2)) and not anymore Math.pow(Math.pow(2, 3), 2). Parentheses can be used to change precedence.
• Remove unsafe j`$(a)$(b)` interpolation deprecated in compiler version 10 #6068
• Remove deprecated module Printexc
• @deriving(jsConverter) not supported anymore for variant types #6088
• New representation for variants, where the tag is a string instead of a number. #6088
• GenType: removed support for @genType.as for records and variants which has become unnecessary. Use the language's @as instead to channge the runtime representation without requiring any runtime conversion during FFI. #6099 #6101

🐛 Bug Fix

• Fix issue where uncurried was not supported with pipe #5803
• Fix printing of nested types in uncurried mode #5826
• Fix issue in printing uncurried callbacks #5828
• Fix formatting uncurried functions with attributes #5829
• Fix parsing/printing uncurried functions with type parameters #5849
• Fix compiler ppx issue when combining async and uncurried application #5856
• Fix issue where the internal representation of uncurried types would leak when a non-function is applied in a curried way #5892
• Fix some comments disappearing in array access expressions #5947
• Parser: fix location of variable when function definition {v => ...} is enclosed in braces #5949
• Fix issue with error messages for uncurried functions where expected and given type were swapped #5973
• Fix issue with integer overflow check #6028
• Make internal encoding of locations aware of unicode #6073
• Fix issue where foo(x,_) in uncurried mode would generate a curried function #6082
• Fix printing of uncurried application when the lhs is a function definition #6084
• Fix parsing uncurried type starting with path #6089
• Fix bigInt comparison #6097
• Fixed a bug where the async attribute was not preserved when using the @this decorator in ReScript functions. This fix allows proper handling of async functions with the @this decorator. Issue: #6100
• Fix issue with GenType and module aliases #6112

💅 Polish

• Syntax: process uncurried types explicitly in the parser/printer #5784 #5822
• Syntax: process uncurried function declarations explicitly in the parser/printer #5794
• PPX V4: allow uncurried make function and treat it like a curried one #5802 #5808 #5812
• Remove processing of objects expressions, which don't exist in .res syntax (Pexp_object) #5841
• Remove class type processing from compiler ppx #5842
• Remove method application via operator ##, which does not exist in .res syntax #5844
• Treat @meth annotation as making the type uncurried for backwards compatibitly with some examples #5845
• Process @set annotation for field update as generating an uncurried function #5846
• Treat uncurried application of primitives like curried application, which produces better output #5851
• New internal representation for uncurried functions using built-in type function$<fun_type, arity> this avoids having to declare all the possible arities ahead of time #5870
• PPX V3: allow uncurried make function and treat it like a curried one https://github.co...

10.1.4

🐛 Bug Fix

• Fix implementation of directives #6052
• Fix issue if the lib dir is included in the sources of bsconfig.json #6055
• Fix issue with string escape in pattern match #6062
• Fix issue with literal comparison of string constants #6065

🚀 New Feature

• Add support for toplevel await #6054

💅 Polish

• Better error message for extension point #6057
• Improve format check help #6056
• Deprecate unsafe j`$(a)$(b)` interpolation: use string templates `${a}${b}` instead #6067

10.1.3

🚀 New Feature

• Add experimental suppport for directives. An annotation such as @@directive("use client;") emits use client; verbatim before imports #5999
• genType: add Core standard library support for the following builtin types: Null.t, Nullable.t, Undefined.t, Dict.t<_>, Promise.t<_>, Date.t, BigInt.t, RegExp.t, Map.t<_, _>, WeakMap.t<_, _>, Set<_>, WeakSet<_> #6024

💥 Breaking Change

• genType: streamline the treatment of optionals as undefined #6024
  • Represent option<t> as undefined | t instead of null | undefined | t. This is more permissive when importing functions taking optional values (allows to use option types), but stricter when e.g. exporting ReScript functions taking arguments of option type. Fallback: use Js.undefined<_> instead.
  • Represent {x:option<string>} as {x:(undefined | string)} instead of {x?: string}. This is more in line with TS's behaviour. Fallback: use {x?:string}.

💅 Polish

• Add the gap property to jsxDOMStyle #5956

🐛 Bug Fix

• Fix issue where error messages related to non-existent props were displayed without location information rescript-lang/syntax#730
• Fix issue where uncurried functions were incorrectly converting the type of a prop given as a default value to curried rescript-lang/syntax#731
• Fix issue with nested async functions, where the inner function would be emitted without async #5984
• Fix issue with printing async functions with locally abstract types rescript-lang/syntax#732
• Fix issue with async context and locally abstract types #5985
• Fix support for recursive components in JSX V4 rescript-lang/syntax#733
• GenType: fix issue with V3 compatibility mode (see #5990) #5992
• Fix issue with overlapping labelled argument with default value rescript-lang/syntax#734
• Fix issue with using alias and default value together rescript-lang/syntax#734
• Fix issue in Js.Promise2 where then and catch were returning undefined #5996
• Fix issue in the compiler back-end where async functions passed to an @uncurry external would be inlined and transformed in a way that loses async #6011
• Fix location issue for the treatment of async functions where hovering on the body with a type error would show 'a => promise<'a> everywhere #6014
• Fix formatting of switch expressions that contain braced cases inside rescript-lang/syntax#735
• Fix formatting of props spread for multiline JSX expression rescript-lang/syntax#736
• Support @gentype.import as an alias to @genType.import in the compiler #6021
• In GenType, check annotations also in module types to decide whether to produce the .gen.tsx file #5903
• Fix issue with JSX V4 and newtype rescript-lang/syntax#737
• Fix issue with JSX V4 when components are nested rescript-lang/syntax#738
• Fix issue where generic compare on float values would be different from the compare for type float #6043
• Improve code generated for default arguments in JSX V4 rescript-lang/syntax#739
• Fix issue with JSX V4 props of the form ~p as module(...) rescript-lang/syntax#739

10.1.2

🐛 Bug Fix

• Fix an issue where error messages related to duplicate props were displayed without a loc and were unclear rescript-lang/syntax#728

10.1.1

💥 Breaking Change

• Parse the attributes of labelled argument to the pattern attributes of argument instead of function. rescript-lang/syntax#722
• The prop names duplicated to keyword are not mangled automatically in JSX v4.
  • Use @as instead

🚀 New Feature

• Add support for empty inlined record literal {} for inlined records where all fields are optional #5900

🐛 Bug Fix

• Prevent inlining of async functions in additional cases #5860
• Revert to ubuntu-18.04 in CI to support Linux versions with older glibc #5868
• Fix build error where aliasing arguments to _ in the make function with JSX V4. rescript-lang/syntax#720
• Fix parsing of spread props as an expression in JSX V4 rescript-lang/syntax#721
• Fix dropping attributes from props in make function in JSX V4 rescript-lang/syntax#723

10.1.0

🐛 Bug Fix

• Fix issue where no error was reported when ? was used for non-optional fields. #5853
• Fix issue where optional fields in inline records were not supported and would cause type errors #5827

10.1.0-rc.5

🐛 Bug Fix

• Prevent inlining of async functions in last stage of the compiler when the functions are not exported (not in interface file or shadowed) #5790

10.1.0-rc.4

🚀 New Feature

• Support format check with rescript format -check. #5760

🐛 Bug Fix

• Fix issue where the last line of rescript format --help usage was being swallowed #5760
• Specialize the printing of the rhs of a record field assignment for optional values {x: ? e} rescript-lang/syntax#714

10.1.0-rc.3

🚀 New Feature

• Support the use of spread anywhere in list creation (e.g. list{...x, 1, ...y, ...z}). rescript-lang/syntax#692
• Add support for the argument of @react.component to set a props type from the outside. rescript-lang/syntax#699

🐛 Bug Fix

• Fix issue where the JSX key type is not an optional string rescript-lang/syntax#693
• Prevent inlining of async functions #5754
• Fix build error for JSX fragment without children rescript-lang/syntax#704
• Fix issue where async as an id cannot be used with application and labelled arguments rescript-lang/syntax#707
• Fix 5557: the exhaustive checking for char is incorrect during the unicode migration #5749
• Fix 5753: the comment for unicode char is inaccurate rescript-lang/syntax#709
• Treat await as almost-unary operator weaker than pipe so await foo->bar means await (foo->bar) rescript-lang/syntax#711

💅 Polish

• Change payload of Pconst_char from char to int rescript-lang/syntax#709

10.1.0-rc.2

🐛 Bug Fix

• Fix issue with changes not being applied with React Native's Metro bundler for files with warnings #5738
• Fix emitting unary minus for floats in case of negative constants #5737
• Fix issue where a spread ...x in non-last position would not be reported as syntax error rescript-lang/syntax#673
• Fix issue where the formatter would delete async in a function with labelled arguments.
• Fix several printing issues with async including an infinite loop rescript-lang/syntax#680
• Fix issue where certain JSX expressions would be formatted differenctly in compiler 10.1.0-rc.1 rescript-lang/syntax#675
• Fix issue where printing nested pipe discards await rescript-lang/syntax#687