Version 4.2.0.pre.1

The first prerelease of the 4.2 line, cut from `master` after 4.1.2.
`Gemfile.lock` is regenerated with the bump, and CHANGELOG.md gains the
4.2.0.pre.1 section.

The changelog starts at `v4.1.2`, the latest tag reachable from `master`,
which is how a prerelease is written up: 4.1.3 was cut from `aaa-4.1.x`,
so the two changes it backported are listed here under the pull requests
they were written in.

The section is the list of pull requests alone. A prerelease carries no
summary paragraphs -- the cycle it belongs to is summarized once, on the
release proper that folds it in -- which docs/release.md now says.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LrJnRwFjCYw9h5U8LkRqqP

Author: claude

CHANGELOG.md

@@ -1,5 +1,32 @@
 # CHANGELOG
 
+## 4.2.0.pre.1 (2026-08-18)
+
+### Language updates
+
+* Gate forwarding parameter syntax behind parser option ([#3087](https://github.com/ruby/rbs/pull/3087))
+* Support non-ASCII identifiers ([#3082](https://github.com/ruby/rbs/pull/3082))
+* Support forwarding parameters in method types ([#3042](https://github.com/ruby/rbs/pull/3042))
+
+### Library changes
+
+* Stop the lexer reading past the end of a byte_range ([#3040](https://github.com/ruby/rbs/pull/3040))
+* Exclude CR from comment tokens to fix an off-by-one Location#end_line on CRLF files ([#3069](https://github.com/ruby/rbs/pull/3069))
+* Handle the NULL parser in the WebAssembly shim ([#3085](https://github.com/ruby/rbs/pull/3085))
+* Reject a byte position the lexer cannot start on ([#3083](https://github.com/ruby/rbs/pull/3083))
+* Don't use Clang nullability qualifiers in strict ISO C mode ([#3074](https://github.com/ruby/rbs/pull/3074))
+* Avoid eagerly inspecting call traces in type assertions ([#3073](https://github.com/ruby/rbs/pull/3073))
+* Fix TypeParam.rename to substitute variables in bounds and default types ([#3068](https://github.com/ruby/rbs/pull/3068))
+* Extract per-declaration type param alignment into entry-level align_params ([#3070](https://github.com/ruby/rbs/pull/3070))
+* Align type params across declarations in module-self types and superclass validation ([#3067](https://github.com/ruby/rbs/pull/3067))
+* Build the wasm module with -DNDEBUG ([#3066](https://github.com/ruby/rbs/pull/3066))
+* Rename NODISCARD macro to RBS_NODISCARD ([#3065](https://github.com/ruby/rbs/pull/3065))
+
+### Miscellaneous
+
+* Skip JSON 2-only tests with JSON 3 ([#3084](https://github.com/ruby/rbs/pull/3084))
+* Pin GitHub Actions to commit hashes ([#3020](https://github.com/ruby/rbs/pull/3020))
+
 ## 4.1.3 (2026-08-10)
 
 ### Miscellaneous

Gemfile.lock

@@ -22,7 +22,7 @@ GIT
 PATH
   remote: .
   specs:
-    rbs (4.2.0.dev)
+    rbs (4.2.0.pre.1)
       logger
       prism (>= 1.6.0)
       tsort

docs/release.md

@@ -101,7 +101,8 @@ The sections always appear in this order; delete the ones that end up empty, whi
 on a small release. Two things scale with the size of the release:
 
 - **Summary paragraphs**, above the first section. A patch release usually has none, 4.1.0 has four
-  paragraphs, and 4.0.0 has nine.
+  paragraphs, and 4.0.0 has nine. A prerelease has none whatever its size: the cycle it belongs to
+  is summarized once, on the release proper that folds it in.
 - **A list of the types whose signatures changed**, as the first line of `### Signature updates`,
   written as `**Updated classes/modules/methods:**` followed by the names in backticks. Used on
   `X.Y.0` releases only.

lib/rbs/version.rb

@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module RBS
-  VERSION = "4.2.0.dev"
+  VERSION = "4.2.0.pre.1"
 end