microsoft · Jake Bailey (jakebailey) · Aug 20, 2026 · Aug 20, 2026 · Aug 20, 2026 · Aug 20, 2026
diff --git a/.custom-gcl.yml b/.custom-gcl.yml
@@ -1,6 +1,6 @@
 # yaml-language-server: $schema=https://golangci-lint.run/jsonschema/custom-gcl.jsonschema.json
 
-version: v2.12.2
+version: v2.13.2
 
 destination: ./tools
 

diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
@@ -1,6 +1,6 @@
 {
     "name": "TypeScript Compiler Development",
-    "image": "mcr.microsoft.com/devcontainers/go:dev-1.26-bookworm",
+    "image": "mcr.microsoft.com/devcontainers/go:1.27-bookworm",
     "features": {
         "ghcr.io/devcontainers/features/node:2": {
             "version": "24",

diff --git a/.dprint.jsonc b/.dprint.jsonc
@@ -38,7 +38,7 @@
         "trailingCommas": "never"
     },
     "gofumpt": {
-        "langVersion": "go1.26",
+        "langVersion": "go1.27",
         "modulePath": "github.com/microsoft/TypeScript/tsc"
     },
     "excludes": [
@@ -66,6 +66,6 @@
         "npm:@dprint/typescript@0.96.1",
         "npm:@dprint/json@0.22.0",
         "npm:dprint-plugin-yaml@0.6.0",
-        "npm:@jakebailey/dprint-plugin-gofumpt@0.0.13"
+        "npm:@jakebailey/dprint-plugin-gofumpt@0.0.16"
     ]
 }
diff --git a/.github/actions/setup-go/action.yml b/.github/actions/setup-go/action.yml
@@ -4,7 +4,7 @@ description: Setup Go
 inputs:
   go-version:
     description: Go version to set up
-    default: '1.26'
+    default: '1.27'
 
 runs:
   using: composite

diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -73,7 +73,6 @@ jobs:
       - name: Tests without Node.js
         run: |
           export PATH="$RUNNER_TEMP/go-test-bin"
-          export GOEXPERIMENT=ms_nocgo_opensslcrypto
           export CGO_ENABLED=0
           ! command -v node
           cd "$RUNNER_TEMP/tsc"

diff --git a/.golangci.yml b/.golangci.yml
@@ -65,17 +65,15 @@ linters:
       customlint:
         type: module
 
-    modernize:
-      disable:
-        - slicesbackward # https://github.com/golang/go/issues/78829
-
     depguard:
       rules:
         main:
           deny:
             - pkg: 'encoding/json$'
               desc: 'Use "github.com/microsoft/TypeScript/tsc/internal/json" instead.'
-            - pkg: 'github.com/go-json-experiment/json'
+            - pkg: 'encoding/json/v2'
+              desc: 'Use "github.com/microsoft/TypeScript/tsc/internal/json" instead.'
+            - pkg: 'encoding/json/jsontext'
               desc: 'Use "github.com/microsoft/TypeScript/tsc/internal/json" instead.'
 
     forbidigo:

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -75,7 +75,7 @@ In general, things we find useful when reviewing suggestions are:
 
 ## Prerequisites
 
-- Go 1.26
+- Go 1.27
 - Node.js 24
 - npm (the version declared by `packageManager` in `package.json`)
 - Git

diff --git a/NOTICE.txt b/NOTICE.txt
@@ -221,37 +221,7 @@ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 
 ---------------------------------------------------------
 
-github.com/go-json-experiment/json v0.0.0-20260623181947-01eb4420fa68 - BSD-3-Clause
-
-
-Copyright 2010 The Go Authors
-Copyright 2011 The Go Authors
-Copyright 2016 The Go Authors
-Copyright 2018 The Go Authors
-Copyright 2020 The Go Authors
-Copyright 2021 The Go Authors
-Copyright 2022 The Go Authors
-Copyright 2023 The Go Authors
-Copyright 2024 The Go Authors
-Copyright (c) 2020 The Go Authors
-
-Copyright (c) <year> <owner> . All rights reserved.
-
-Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
-
-   1. Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
-
-   2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
-
-   3. Neither the name of the copyright holder nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
----------------------------------------------------------
-
----------------------------------------------------------
-
-golang.org/x/sync v0.21.0 - BSD-3-Clause AND LicenseRef-scancode-google-patent-license-golang
+golang.org/x/sync v0.22.0 - BSD-3-Clause AND LicenseRef-scancode-google-patent-license-golang
 
 
 Copyright 2009 The Go Authors
@@ -266,7 +236,7 @@ BSD-3-Clause AND LicenseRef-scancode-google-patent-license-golang
 
 ---------------------------------------------------------
 
-golang.org/x/sys v0.46.0 - BSD-3-Clause AND LicenseRef-scancode-google-patent-license-golang
+golang.org/x/sys v0.47.0 - BSD-3-Clause AND LicenseRef-scancode-google-patent-license-golang
 
 
 Copyright 2009 The Go Authors
@@ -294,7 +264,7 @@ BSD-3-Clause AND LicenseRef-scancode-google-patent-license-golang
 
 ---------------------------------------------------------
 
-golang.org/x/term v0.44.0 - BSD-3-Clause AND LicenseRef-scancode-google-patent-license-golang
+golang.org/x/term v0.45.0 - BSD-3-Clause AND LicenseRef-scancode-google-patent-license-golang
 
 
 Copyright 2009 The Go Authors
@@ -309,7 +279,7 @@ BSD-3-Clause AND LicenseRef-scancode-google-patent-license-golang
 
 ---------------------------------------------------------
 
-golang.org/x/text v0.38.0 - BSD-3-Clause AND LicenseRef-scancode-google-patent-license-golang
+golang.org/x/text v0.41.0 - BSD-3-Clause AND LicenseRef-scancode-google-patent-license-golang
 
 
 (c) AeHa (c)
@@ -381,7 +351,7 @@ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLI
 
 ---------------------------------------------------------
 
-github.com/mackerelio/go-osstat v0.2.7 - Apache-2.0
+github.com/mackerelio/go-osstat v0.2.8 - Apache-2.0
 
 
 Copyright 2017-2019 Hatena Co., Ltd.
@@ -433,4 +403,3 @@ SOFTWARE.
 
 
 ---------------------------------------------------------
-
diff --git a/go.work b/go.work
@@ -1,4 +1,4 @@
-go 1.26
+go 1.27
 
 use (
 	./tools

diff --git a/tools/customlint/testdata/go.mod b/tools/customlint/testdata/go.mod
@@ -1,3 +1,3 @@
 module testdata
 
-go 1.26
+go 1.27
diff --git a/tools/go.mod b/tools/go.mod
@@ -1,13 +1,13 @@
 module github.com/microsoft/TypeScript/tools
 
-go 1.26
+go 1.27
 
 require (
 	github.com/anchore/quill v0.7.1
 	github.com/blacktop/go-macho v1.1.263
 	github.com/golangci/plugin-module-register v0.1.2
-	golang.org/x/mod v0.37.0
-	golang.org/x/tools v0.47.0
+	golang.org/x/mod v0.40.0
+	golang.org/x/tools v0.49.0
 	gotest.tools/v3 v3.5.2
 )
 
@@ -21,7 +21,7 @@ require (
 	github.com/google/uuid v1.6.0 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/scylladb/go-set v1.0.3-0.20200225121959-cc7b2070d91e // indirect
-	golang.org/x/crypto v0.53.0 // indirect
-	golang.org/x/sync v0.21.0 // indirect
+	golang.org/x/crypto v0.55.0 // indirect
+	golang.org/x/sync v0.22.0 // indirect
 	software.sslmate.com/src/go-pkcs12 v0.7.2 // indirect
 )
diff --git a/tools/go.sum b/tools/go.sum
@@ -51,22 +51,22 @@ github.com/stretchr/testify v1.11.1 h1:7s2iGBzp5EwR7/aIZr8ao5+dra3wiQyKjjFuvgVKu
 github.com/stretchr/testify v1.11.1/go.mod h1:wZwfW3scLgRK+23gO65QZefKpKQRnfz6sD981Nm4B6U=
 golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
 golang.org/x/crypto v0.0.0-20190426145343-a29dc8fdc734/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
-golang.org/x/crypto v0.53.0 h1:QZ4Muo8THX6CizN2vPPd5fBGHyogrdK9fG4wLPFUsto=
-golang.org/x/crypto v0.53.0/go.mod h1:DNLU434OwVakk9PzuwV8w62mAJpRJL3vsgcfp4Qnsio=
-golang.org/x/mod v0.37.0 h1:vF1DjpVEshcIqoEaauuHebaLk1O1forxjxBaVn884JQ=
-golang.org/x/mod v0.37.0/go.mod h1:m8S8VeM9r4dzDwjrKO0a1sZP3YjeMamRRlD+fmR2Q/0=
+golang.org/x/crypto v0.55.0 h1:+KWHjbgOaAQ66dh/YlkZKHlz9ZUlq61AFirAR9ntP8M=
+golang.org/x/crypto v0.55.0/go.mod h1:uq0V9dE/fzQuJtbnL+2EhWOE63vo164FY8xqEnV9xis=
+golang.org/x/mod v0.40.0 h1:hUv+3cXcdRHz08UmSiOob7sadHig73uo5bkXxQ/tvUs=
+golang.org/x/mod v0.40.0/go.mod h1:0/weTWkPWGBikyTWAX3dkjVztMmBA5hM0DH6BElSupE=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
-golang.org/x/sync v0.21.0 h1:HLII4xRRTtCRkxYp4HNFF0Js/Og6q2i++KXbg0gHCwM=
-golang.org/x/sync v0.21.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
+golang.org/x/sync v0.22.0 h1:SZjpbeLmrCk4xhRSZFNZW5gFUeCeFgjekvI/+gfScek=
+golang.org/x/sync v0.22.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.46.0 h1:noSf2Fq6F8DBgS+LysIkx7rIExoNHJsxOAtPp4rthXw=
-golang.org/x/sys v0.46.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
-golang.org/x/term v0.44.0 h1:0rLvDRCtNj0gZkyIXhCyOb2OAzEhLVqc4B+hrsBhrmc=
-golang.org/x/term v0.44.0/go.mod h1:7ze4MdzUzLXpSAoFP1H0bOI9aXDqveSvatT5vKcFh2Y=
+golang.org/x/sys v0.47.0 h1:o7XGOvZQCADBQQ4Y7VNq2dRWQR7JmOUW8Kxx4ZsNgWs=
+golang.org/x/sys v0.47.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
+golang.org/x/term v0.45.0 h1:NwWyBmoJCbfTHpxrWoZ9C6/VxOf7ic219I8xZZFdrf0=
+golang.org/x/term v0.45.0/go.mod h1:9aqxs0blBcrm/n0L9QW0aRVD+ktan8ssZromtqJC43w=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
-golang.org/x/tools v0.47.0 h1:7Kn5x/d1svx/PzryTsqeoZN4TZwqeH5pGWjefhLi/1Q=
-golang.org/x/tools v0.47.0/go.mod h1:dFHnyTvFWY212G+h7ZY4Vsp/K3U4/7W9TyVaAul8uCA=
+golang.org/x/tools v0.49.0 h1:3NI7VXzL9+1WZD52Dx2ttoPwD5DWrFGpl9mFZDlmisI=
+golang.org/x/tools v0.49.0/go.mod h1:SJNXV9DBKT0UbdttsQjbfJlAE/q+y36++zo3uL3N0Oo=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=

diff --git a/tsc/go.mod b/tsc/go.mod
@@ -1,28 +1,27 @@
 module github.com/microsoft/TypeScript/tsc
 
-go 1.26
+go 1.27
 
 require (
 	github.com/Microsoft/go-winio v0.6.2
-	github.com/go-json-experiment/json v0.0.0-20260623181947-01eb4420fa68
 	github.com/google/go-cmp v0.7.0
 	github.com/klauspost/compress v1.19.0
-	github.com/mackerelio/go-osstat v0.2.7
+	github.com/mackerelio/go-osstat v0.2.8
 	github.com/peter-evans/patience v0.3.0
 	github.com/zeebo/xxh3 v1.1.0
-	golang.org/x/sync v0.21.0
-	golang.org/x/sys v0.46.0
-	golang.org/x/term v0.44.0
-	golang.org/x/text v0.38.0
+	golang.org/x/sync v0.22.0
+	golang.org/x/sys v0.47.0
+	golang.org/x/term v0.45.0
+	golang.org/x/text v0.41.0
 	gotest.tools/v3 v3.5.2
 )
 
 require (
 	github.com/klauspost/cpuid/v2 v2.2.10 // indirect
 	github.com/matryer/moq v0.7.1 // indirect
 	github.com/pmezard/go-difflib v1.0.1-0.20181226105442-5d4384ee4fb2 // indirect
-	golang.org/x/mod v0.37.0 // indirect
-	golang.org/x/tools v0.47.0 // indirect
+	golang.org/x/mod v0.40.0 // indirect
+	golang.org/x/tools v0.49.0 // indirect
 )
 
 tool (

diff --git a/tsc/go.sum b/tsc/go.sum
@@ -1,15 +1,13 @@
 github.com/Microsoft/go-winio v0.6.2 h1:F2VQgta7ecxGYO8k3ZZz3RS8fVIXVxONVUPlNERoyfY=
 github.com/Microsoft/go-winio v0.6.2/go.mod h1:yd8OoFMLzJbo9gZq8j5qaps8bJ9aShtEA8Ipt1oGCvU=
-github.com/go-json-experiment/json v0.0.0-20260623181947-01eb4420fa68 h1:KZaTBSyshWX3MP5jukJcNSuXDQTO+rNpt0J564dX/eg=
-github.com/go-json-experiment/json v0.0.0-20260623181947-01eb4420fa68/go.mod h1:tphK2c80bpPhMOI4v6bIc2xWywPfbqi1Z06+RcrMkDg=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
 github.com/google/go-cmp v0.7.0/go.mod h1:pXiqmnSA92OHEEa9HXL2W4E7lf9JzCmGVUdgjX3N/iU=
 github.com/klauspost/compress v1.19.0 h1:sXLILfc9jV2QYWkzFOPWStmcUVH2RHEB1JCdY2oVvCQ=
 github.com/klauspost/compress v1.19.0/go.mod h1:cwPg85FWrGar70rWktvGQj8/hthj3wpl0PGDogxkrSQ=
 github.com/klauspost/cpuid/v2 v2.2.10 h1:tBs3QSyvjDyFTq3uoc/9xFpCuOsJQFNPiAhYdw2skhE=
 github.com/klauspost/cpuid/v2 v2.2.10/go.mod h1:hqwkgyIinND0mEev00jJYCxPNVRVXFQeu1XKlok6oO0=
-github.com/mackerelio/go-osstat v0.2.7 h1:TCavZi10wF49bT6iQZ9eT2keGZQpC69MTDfdJej5e94=
-github.com/mackerelio/go-osstat v0.2.7/go.mod h1:dwpYh5pIPmvk+IEwBKNIWRFMB92mrC08CmXOhDC7nQk=
+github.com/mackerelio/go-osstat v0.2.8 h1:I2duicTaCGWoM53XwAwA9OIe1inu0xnVs8/pqOWWVr4=
+github.com/mackerelio/go-osstat v0.2.8/go.mod h1:SyS3XxKdoSKJnTGTkN5Yrh6VUQVuAURACfE6y+2DN4k=
 github.com/matryer/moq v0.7.1 h1:/QaXqMAdOrLqlshW2z7SMS21jDi7aVrbW0wJrR+hhJk=
 github.com/matryer/moq v0.7.1/go.mod h1:IabIiFkaKCyHxej25INgFR+fnOxSZFMv2LYrU+ioyDs=
 github.com/peter-evans/patience v0.3.0 h1:rX0JdJeepqdQl1Sk9c9uvorjYYzL2TfgLX1adqYm9cA=
@@ -20,17 +18,17 @@ github.com/zeebo/assert v1.3.0 h1:g7C04CbJuIDKNPFHmsk4hwZDO5O+kntRxzaUoNXj+IQ=
 github.com/zeebo/assert v1.3.0/go.mod h1:Pq9JiuJQpG8JLJdtkwrJESF0Foym2/D9XMU5ciN/wJ0=
 github.com/zeebo/xxh3 v1.1.0 h1:s7DLGDK45Dyfg7++yxI0khrfwq9661w9EN78eP/UZVs=
 github.com/zeebo/xxh3 v1.1.0/go.mod h1:IisAie1LELR4xhVinxWS5+zf1lA4p0MW4T+w+W07F5s=
-golang.org/x/mod v0.37.0 h1:vF1DjpVEshcIqoEaauuHebaLk1O1forxjxBaVn884JQ=
-golang.org/x/mod v0.37.0/go.mod h1:m8S8VeM9r4dzDwjrKO0a1sZP3YjeMamRRlD+fmR2Q/0=
-golang.org/x/sync v0.21.0 h1:HLII4xRRTtCRkxYp4HNFF0Js/Og6q2i++KXbg0gHCwM=
-golang.org/x/sync v0.21.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
-golang.org/x/sys v0.46.0 h1:noSf2Fq6F8DBgS+LysIkx7rIExoNHJsxOAtPp4rthXw=
-golang.org/x/sys v0.46.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
-golang.org/x/term v0.44.0 h1:0rLvDRCtNj0gZkyIXhCyOb2OAzEhLVqc4B+hrsBhrmc=
-golang.org/x/term v0.44.0/go.mod h1:7ze4MdzUzLXpSAoFP1H0bOI9aXDqveSvatT5vKcFh2Y=
-golang.org/x/text v0.38.0 h1:sXmwo9DwP3OK9EZ7PqAdaooSGozfl/3a6/xJcbzPRhE=
-golang.org/x/text v0.38.0/go.mod h1:YXZt3QhHUKYT53r2lLKFIVi6Ao1jdzrTR/KQ09qyxF4=
-golang.org/x/tools v0.47.0 h1:7Kn5x/d1svx/PzryTsqeoZN4TZwqeH5pGWjefhLi/1Q=
-golang.org/x/tools v0.47.0/go.mod h1:dFHnyTvFWY212G+h7ZY4Vsp/K3U4/7W9TyVaAul8uCA=
+golang.org/x/mod v0.40.0 h1:hUv+3cXcdRHz08UmSiOob7sadHig73uo5bkXxQ/tvUs=
+golang.org/x/mod v0.40.0/go.mod h1:0/weTWkPWGBikyTWAX3dkjVztMmBA5hM0DH6BElSupE=
+golang.org/x/sync v0.22.0 h1:SZjpbeLmrCk4xhRSZFNZW5gFUeCeFgjekvI/+gfScek=
+golang.org/x/sync v0.22.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
+golang.org/x/sys v0.47.0 h1:o7XGOvZQCADBQQ4Y7VNq2dRWQR7JmOUW8Kxx4ZsNgWs=
+golang.org/x/sys v0.47.0/go.mod h1:4GL1E5IUh+htKOUEOaiffhrAeqysfVGipDYzABqnCmw=
+golang.org/x/term v0.45.0 h1:NwWyBmoJCbfTHpxrWoZ9C6/VxOf7ic219I8xZZFdrf0=
+golang.org/x/term v0.45.0/go.mod h1:9aqxs0blBcrm/n0L9QW0aRVD+ktan8ssZromtqJC43w=
+golang.org/x/text v0.41.0 h1:vz/seA0lnX87Othu2f/0L24RcgrXD9/YFTSuGjj3rH8=
+golang.org/x/text v0.41.0/go.mod h1:jvf1O8ajNzZqhSrQBPbutR/EB83Cc0CFrezNQIwbb5M=
+golang.org/x/tools v0.49.0 h1:3NI7VXzL9+1WZD52Dx2ttoPwD5DWrFGpl9mFZDlmisI=
+golang.org/x/tools v0.49.0/go.mod h1:SJNXV9DBKT0UbdttsQjbfJlAE/q+y36++zo3uL3N0Oo=
 gotest.tools/v3 v3.5.2 h1:7koQfIKdy+I8UTetycgUqXWSDwpgv193Ka+qRsmBY8Q=
 gotest.tools/v3 v3.5.2/go.mod h1:LtdLGcnqToBH83WByAAi/wiwSFCArdFIUV/xxN4pcjA=
diff --git a/tsc/internal/api/encoder/encoder.go b/tsc/internal/api/encoder/encoder.go
@@ -406,7 +406,7 @@ func BuildNodeIndexTable(sourceFile *ast.SourceFile) *NodeIndexTable {
 }
 
 func GetNodeIndexTable(sourceFile *ast.SourceFile) *NodeIndexTable {
-	return ast.GetOrComputeSourceFileData(sourceFile, nodeIndexTableKey, BuildNodeIndexTable)
+	return sourceFile.GetOrComputeData(nodeIndexTableKey, BuildNodeIndexTable)
 }
 
 // EncodeSourceFile encodes an entire source file AST into the binary format.
@@ -416,7 +416,7 @@ func EncodeSourceFile(sourceFile *ast.SourceFile) ([]byte, *NodeIndexTable, erro
 	if err != nil {
 		return nil, nil, err
 	}
-	nodeTable = ast.GetOrComputeSourceFileData(sourceFile, nodeIndexTableKey, func(*ast.SourceFile) *NodeIndexTable {
+	nodeTable = sourceFile.GetOrComputeData(nodeIndexTableKey, func(*ast.SourceFile) *NodeIndexTable {
 		return nodeTable
 	})
 	return data, nodeTable, nil

diff --git a/tsc/internal/ast/ast.go b/tsc/internal/ast/ast.go
@@ -2414,15 +2414,15 @@ func NewSourceFileDataKey[T any]() *SourceFileDataKey[T] {
 	return &SourceFileDataKey[T]{key: sourceFileDataKey(sourceFileDataKeyCounter.Add(1))}
 }
 
-func GetOrComputeSourceFileData[T any](file *SourceFile, key *SourceFileDataKey[T], compute func(*SourceFile) T) T {
-	cell := getSourceFileDataCell(file, key)
+func (file *SourceFile) GetOrComputeData[T any](key *SourceFileDataKey[T], compute func(*SourceFile) T) T {
+	cell := file.getDataCell(key)
 	cell.once.Do(func() {
 		cell.value = compute(file)
 	})
 	return cell.value
 }
 
-func getSourceFileDataCell[T any](file *SourceFile, key *SourceFileDataKey[T]) *sourceFileDataCell[T] {
+func (file *SourceFile) getDataCell[T any](key *SourceFileDataKey[T]) *sourceFileDataCell[T] {
 	if key == nil || key.key == 0 {
 		panic("invalid SourceFileDataKey; use NewSourceFileDataKey")
 	}

diff --git a/tsc/internal/astnav/tokens.go b/tsc/internal/astnav/tokens.go
@@ -2,6 +2,7 @@ package astnav
 
 import (
 	"fmt"
+	"slices"
 
 	"github.com/microsoft/TypeScript/tsc/internal/ast"
 	"github.com/microsoft/TypeScript/tsc/internal/core"
@@ -142,9 +143,9 @@ func getTokenAtPosition(
 			if nodeList.End() == position && includePrecedingTokenAtEndPosition != nil {
 				left = nodeList.End()
 				nodeAfterLeft = nil
-				for i := len(nodeList.Nodes) - 1; i >= 0; i-- {
-					if nodeList.Nodes[i].Flags&ast.NodeFlagsReparsed == 0 {
-						prevSubtree = nodeList.Nodes[i]
+				for _, v := range slices.Backward(nodeList.Nodes) {
+					if v.Flags&ast.NodeFlagsReparsed == 0 {
+						prevSubtree = v
 						break
 					}
 				}
@@ -416,9 +417,9 @@ func FindPrecedingTokenEx(sourceFile *ast.SourceFile, position int, startNode *a
 					// Find jsdoc preceding the foundChild.
 					var jsDoc *ast.Node
 					nodeJSDoc := n.JSDoc(sourceFile)
-					for i := len(nodeJSDoc) - 1; i >= 0; i-- {
-						if nodeJSDoc[i].Pos() >= foundChild.Pos() {
-							jsDoc = nodeJSDoc[i]
+					for _, n := range slices.Backward(nodeJSDoc) {
+						if n.Pos() >= foundChild.Pos() {
+							jsDoc = n
 							break
 						}
 					}
-Original file line number
+Diff line change
@@ Expand Up @@
     ## Prerequisites
-    - Go 1.26
+    - Go 1.27
     - Node.js 24
     - npm (the version declared by `packageManager` in `package.json`)
     - Git
@@ Expand Down @@