Add Visual Studio 2026 (version 18.0) support to capability detection (#5406)

* Initial plan

* Add Visual Studio 2026 (version 18.0) support

Co-authored-by: tarunramsinghani <2929463+tarunramsinghani@users.noreply.github.com>

* Fix typo in comment - remove extra comma

Co-authored-by: tarunramsinghani <2929463+tarunramsinghani@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: tarunramsinghani <2929463+tarunramsinghani@users.noreply.github.com>

Author: Copilot

src/Misc/layoutbin/powershell/Add-MSBuildCapabilities.ps1

@@ -65,6 +65,8 @@ Get-MSBuildCapabilities -MajorVersion 16
 
 Get-MSBuildCapabilities -MajorVersion 17
 
+Get-MSBuildCapabilities -MajorVersion 18
+
 # Add 64-bit.
 $latest = $null
 $null = Add-CapabilityFromRegistry -Name "MSBuild_2.0_x64" -Hive 'LocalMachine' -View 'Registry64' -KeyName $keyName20 -ValueName 'MSBuildToolsPath' -Value ([ref]$latest)
@@ -85,3 +87,5 @@ if ($vs15 -and $vs15.installationPath) {
 Get-MSBuildCapabilities -MajorVersion 16 -Add_x64
 
 Get-MSBuildCapabilities -MajorVersion 17 -Add_x64
+
+Get-MSBuildCapabilities -MajorVersion 18 -Add_x64

src/Misc/layoutbin/powershell/Add-VisualStudioCapabilities.ps1

@@ -30,7 +30,7 @@ function Add-TestCapability {
 function Get-VSCapabilities {
     param (
         [Parameter(Mandatory = $true)]
-        [ValidateSet(15, 16, 17)]
+        [ValidateSet(15, 16, 17, 18)]
         [int]$MajorVersion,
 
         [Parameter(Mandatory = $true)]
@@ -87,6 +87,7 @@ $keyName14 = 'Software\Microsoft\VisualStudio\14.0'
 $keyName15 = 'Software\Microsoft\VisualStudio\15.0'
 $keyName16 = 'Software\Microsoft\VisualStudio\16.0'
 $keyName17 = 'Software\Microsoft\VisualStudio\17.0'
+$keyName18 = 'Software\Microsoft\VisualStudio\18.0'
 
 # Add the capabilities.
 $latestVS = $null
@@ -111,3 +112,5 @@ Get-VSCapabilities -MajorVersion 15 -keyName $keyName15
 Get-VSCapabilities -MajorVersion 16 -keyName $keyName16
 
 Get-VSCapabilities -MajorVersion 17 -keyName $keyName17
+
+Get-VSCapabilities -MajorVersion 18 -keyName $keyName18

src/Misc/layoutbin/powershell/CapabilityHelpers/VisualStudioFunctions.ps1

@@ -2,14 +2,14 @@ function Get-VisualStudio {
     [CmdletBinding()]
     param(
         [Parameter(Mandatory = $true)]
-        [ValidateSet(15, 16, 17)]
+        [ValidateSet(15, 16, 17, 18)]
         [int]$MajorVersion
         )
 
     try {
-        # Query for the latest 15.*/16.*/17.* version.
+        # Query for the latest 15.*/16.*/17.*/18.* version.
         #
-        # Note, the capability is registered as VisualStudio_15.0/VisualStudio_16.0/VisualStudio_17.0 however the actual
+        # Note, the capability is registered as VisualStudio_15.0/VisualStudio_16.0/VisualStudio_17.0/VisualStudio_18.0 however the actual
         # version may something like 15.2/16.2.
         $preReleaseFlag = [string]::Empty;
         if ($env:IncludePrereleaseVersions -eq $true)