CHANGELOG.md

Changelog

Unreleased

Compiler

• Optimised code generated for record updates. (yoshi)

• The compiler now allows for record updates to change the generic type parameters of the record:

  type Box(value) {
    Box(password: String, value: value)
  }
  
  fn insert(box: Box(a), value: b) -> Box(b) {
    Box(..box, value:)
  }

  (yoshi)

• It is now allowed to write a block with no expressions. Like an empty function body, an empty block is considered incomplete as if it contained a todo expression. (Giacomo Cavalieri)

• The shorthand names for the two targets, erl and js are now deprecated in code such as @target. (Surya Rose)

• When targeting JavaScript the compiler now generates faster and smaller code for Int values in bit array expressions and patterns by evaluating them at compile time where possible. (Richard Viney)

Build tool

• Improved the error message you get when trying to add a package that doesn't exist with gleam add. (Giacomo Cavalieri)

• FFI files (such as .mjs and .erl) are now permitted in subdirectories of src/ and test/. (PgBiel)

Language Server

• The language server now provides type information when hovering over argument labels. (Surya Rose)

• The Language Server now suggests a code action to desugar a use expression into the equivalent function call. For example, this snippet of code:

  pub fn main() {
    use profile <- result.try(fetch_profile(user))
    render_welcome(user, profile)
  }

  Will be turned into:

  pub fn main() {
    result.try(fetch_profile(user), fn(profile) {
      render_welcome(user, profile)
    })
  }

  (Giacomo Cavalieri)

• The Language Server now suggests a code action to turn a function call into the equivalent use expression. For example, this snippet of code:

  pub fn main() {
    result.try(fetch_profile(user) fn(profile) {
      render_welcome(user, profile)
    })
  }

  Will be turned into:

  pub fn main() {
    use profile <- result.try(fetch_profile(user))
    render_welcome(user, profile)
  }

  (Giacomo Cavalieri)

• The language server now provides correct information when hovering over patterns in use expressions. (Surya Rose)

Formatter

• The formatter now adds a todo inside empty blocks. (Giacomo Cavalieri)

Bug fixed

• The compiler now throws an error when a float literal ends with an e and is missing an exponent. (Surya Rose)

• Fixed a crash with ENOTEMPTY (os error 39) when building on NTFS partitions (Ivan Ermakov)

• Fixed a bug where the compiler would crash when pattern matching on multiple subjects and one of them being a constant record. (Surya Rose)

• Variant inference on prelude types now works correctly if the variant is constant. (Surya Rose)

• Fixed a bug where patterns in use expressions would not be checked to ensure that they were exhaustive. (Surya Rose)

• Fixed a bug where a module.mjs file would be overwritten by a module.gleam file of same name without warning. It now produces an error. (PgBiel)

v1.6.1 - 2024-11-19

Bug fixed

• Fixed a bug where gleam update would fail to update versions. (Jason Sipula)