Implement basic nested language detection support

.github/workflows/build.yml

@@ -57,7 +57,13 @@ jobs:
     name: Build on ${{matrix.os}} for ${{ matrix.label }} ${{ matrix.workspace-loader }} ${{ matrix.use-transparent-compiler }}
 
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
+      if: ${{ github.event_name == 'pull_request' }}
+      with:
+        ref: ${{ github.event.pull_request.head.sha }}
+
+    - uses: actions/checkout@v4
+      if: ${{ github.event_name == 'push' }}
 
     # setup .NET per the repo global.json
     - name: Setup .NET

.vscode/launch.json

@@ -9,7 +9,10 @@
       "type": "coreclr",
       "request": "launch",
       "program": "${workspaceFolder}/src/FsAutoComplete/bin/Debug/net8.0/fsautocomplete.dll",
-      "args": ["--mode", "lsp"],
+      "args": [
+        "--mode",
+        "lsp"
+      ],
       "cwd": "${workspaceFolder}",
       "console": "internalConsole",
       "stopAtEntry": false,
@@ -47,7 +50,11 @@
         }
       },
       "enableStepFiltering": false,
-      "args": ["--debug", "--filter", "FSAC.lsp.${input:loader}.${input:compiler}.${input:testName}"],
+      "args": [
+        "--debug",
+        "--filter",
+        "FSAC.lsp.${input:loader}.${input:compiler}.${input:testName}"
+      ],
       "preLaunchTask": "build debug"
     },
     {
@@ -69,29 +76,42 @@
         }
       },
       "enableStepFiltering": false,
-      "args": ["--debug", "--filter", "FSAC.general.${input:testName}"],
+      "args": [
+        "--debug",
+        "--filter",
+        "FSAC.general.${input:testName}"
+      ],
       "preLaunchTask": "build debug"
     }
   ],
   "inputs": [
     {
       "id": "tfm",
       "description": "The TFM of the test to run",
-      "options": ["net8.0", "net9.0"],
+      "options": [
+        "net8.0",
+        "net9.0"
+      ],
       "default": "net8.0",
       "type": "pickString"
     },
     {
       "id": "loader",
       "description": "The loader to use for the test",
-      "options": ["Ionide WorkspaceLoader", "MSBuild Project Graph WorkspaceLoader"],
+      "options": [
+        "Ionide WorkspaceLoader",
+        "MSBuild Project Graph WorkspaceLoader"
+      ],
       "default": "WorkspaceLoader",
       "type": "pickString"
     },
     {
       "id": "compiler",
       "description": "The compiler to use",
-      "options": ["BackgroundCompiler", "TransparentCompiler"],
+      "options": [
+        "BackgroundCompiler",
+        "TransparentCompiler"
+      ],
       "default": "BackgroundCompiler",
       "type": "pickString"
     },
@@ -101,4 +121,4 @@
       "type": "promptString"
     }
   ]
-}
+}

Directory.Build.props

@@ -14,6 +14,7 @@
     <WarnOn>$(WarnOn);3390</WarnOn><!-- Malformed XML doc comments -->
         <!-- Package Reference with no usable assets -->
     <NoWarn>$(NoWarn);NU1701</NoWarn>
+    <NoWarn>$(NoWarn);NU1510</NoWarn>
     <TreatWarningsAsErrors>true</TreatWarningsAsErrors>
     <ChangelogFile>$(MSBuildThisFileDirectory)CHANGELOG.md</ChangelogFile>
     <!-- Only the tool package is packable -->

global.json

@@ -4,4 +4,4 @@
     "rollForward": "latestMajor",
     "allowPrerelease": true
   }
-}
+}

src/Directory.Build.props

@@ -10,8 +10,8 @@
     <NoWarn>$(NoWarn);NU5104</NoWarn>
     <!-- Yes we know 'times' is for test only, thanks FSC :) -->
     <NoWarn>$(NoWarn);FS0075</NoWarn>
-    <!-- Implicit convertions for string should be fine https://github.com/fsharp/fslang-design/blob/main/FSharp-6.0/FS-1093-additional-conversions.md#motivation-for-op_implicit-type-directed-conversion -->
-    <NoWarn>$(NoWarn);FS3391</NoWarn>
+    <!-- Implicit conversions for string should be fine https://github.com/fsharp/fslang-design/blob/main/FSharp-6.0/FS-1093-additional-conversions.md#motivation-for-op_implicit-type-directed-conversion -->
+    <NoWarn>$(NoWarn);FS3391;NU1510</NoWarn>
     <OtherFlags>$(OtherFlags) --test:GraphBasedChecking --test:DumpCheckingGraph</OtherFlags>
   </PropertyGroup>
 </Project>

src/FsAutoComplete.Core/Commands.fs

@@ -84,6 +84,10 @@ type NotificationEvent =
   | Canceled of errorMessage: string
   | FileParsed of string<LocalPath>
   | TestDetected of file: string<LocalPath> * tests: TestAdapter.TestAdapterEntry<range>[]
+  | NestedLanguagesFound of
+    file: string<LocalPath> *
+    version: int *
+    nestedLanguages: NestedLanguages.NestedLanguageDocument array
 
 module Commands =
   open System.Collections.Concurrent

src/FsAutoComplete.Core/FsAutoComplete.Core.fsproj

@@ -4,6 +4,7 @@
     <TargetFrameworks Condition="'$(BuildNet9)' == 'true'">net8.0;net9.0</TargetFrameworks>
     <IsPackable>false</IsPackable>
     <NoWarn>$(NoWarn);FS0057</NoWarn> <!-- Allows using experimental FCS APIs -->
+    <LangVersion>preview</LangVersion>
   </PropertyGroup>
   <ItemGroup>
     <ProjectReference Include="..\FsAutoComplete.Logging\FsAutoComplete.Logging.fsproj" />
@@ -61,6 +62,7 @@
     <Compile Include="SignatureHelp.fs" />
     <Compile Include="InlayHints.fs" />
     <Compile Include="SymbolLocation.fs" />
+    <Compile Include="NestedLanguages.fs" />
     <Compile Include="Commands.fs" />
   </ItemGroup>
   <Import Project="..\..\.paket\Paket.Restore.targets" />