`LinterCop analyzer crashes (AD0001 MissingMethodException) when AL Language extension DevTools are newer than bundled ALCops.Analyzers`

[fvet]

Follow-up on #8

---

Description

When using alcops-mcp with the AL Language VS Code extension installed, the analyze tool returns AD0001 because the bundled LinterCop analyzer throws at runtime:

System.MissingMethodException: Method not found:
'System.String Microsoft.Dynamics.Nav.CodeAnalysis.Utilities.StringExtensions.QuoteIdentifierIfNeeded(System.String)'
   at ALCops.LinterCop.Analyzers.InternalProcedureNotReferenced.MethodSymbolAnalyzer.ReportUnchangedReferencePassedParameters(...)
   at ALCops.LinterCop.Analyzers.InternalProcedureNotReferenced.CheckApplicationObjects(...)

This appears to be a BC Development Tools version mismatch: the MCP server resolves DevTools from the AL Language extension (step 2 in BC Development Tools Resolution), but the bundled ALCops.Analyzers were compiled against an older DevTools build.

Other LinterCop rules that depend on the same analyzer (for example unused internal procedures) are silently skipped when this crash occurs.

---

Steps to reproduce

1. Install AL Language VS Code extension (recent v17 build).

2. Install the MCP server: dotnet tool install -g ALCops.Mcp (tested with 0.1.0-alpha.7).

3. Configure Cursor / Claude with:

   {
     "mcpServers": {
       "alcops": {
         "command": "alcops-mcp"
       }
     }
   }

4. Open a small AL project with code analysis enabled and at least one unused internal procedure (optional, to show missing LinterCop diagnostics).

5. Call the MCP analyze tool with minSeverity: "Warning".

---

Actual behavior

• AD0001 warning: LinterCop analyzer InternalProcedureNotReferenced throws MissingMethodException.

• Only non-LinterCop warnings are returned reliably (for example CodeCop AA0228).

• On MCP startup (stderr), DevTools resolve to the AL extension:

  BC DevTools: C:\Users\<user>\.vscode\extensions\ms-dynamics-smb.al-17.0.2273547\bin\Analyzers
  

Example diagnostic payload:

{
  "id": "AD0001",
  "message": "Analyzer 'ALCops.LinterCop.Analyzers.InternalProcedureNotReferenced' threw an exception of type 'System.MissingMethodException' ... QuoteIdentifierIfNeeded ...",
  "severity": "Warning",
  "copName": "Unknown",
  "hasCodeFix": false
}

---

Expected behavior

• LinterCop analyzers run without crashing.
• DevTools version used at runtime matches the version ALCops.Analyzers was built against, or the MCP server selects a compatible pair automatically.
• Rules such as unused internal procedures are reported when applicable.

---

Environment

Component	Version
OS	Windows 10 (10.0.26200)
MCP client	Cursor
alcops-mcp (ALCops.Mcp)	0.1.0-alpha.7
Bundled ALCops.LinterCop.dll	0.5.0
Bundled target (from ALCops.Mcp.deps.json)	Microsoft.Dynamics.Nav.CodeAnalysis 17.0.33.55542
AL Language VS Code extension	ms-dynamics-smb.al 17.0.2273547
Resolved Microsoft.Dynamics.Nav.CodeAnalysis.dll (from extension bin\Analyzers)	17.0.34.45391
BCDEVELOPMENTTOOLSPATH	(not set)
~/.alcops/cache/devtools/	(empty before manual download)

NuGet DevTools versions confirmed on nuget.org:

• 17.0.33.55542 — matches bundled ALCops.Analyzers dependency
• 17.0.34.45391 — matches current AL Language extension

---

Root cause analysis

Per MCP Server — BC Development Tools Resolution, when BCDEVELOPMENTTOOLSPATH is unset and the AL Language extension is installed, the server always prefers the extension’s DevTools over the local cache or NuGet auto-download.

In this setup:

1. ALCops.Analyzers 0.5.0 (shipped inside alcops-mcp) targets DevTools 17.0.33.55542.
2. The AL Language extension supplies DevTools 17.0.34.45391.
3. A breaking API change between those patch releases (StringExtensions.QuoteIdentifierIfNeeded) causes LinterCop to fail at runtime.

This matches the general “version mismatch between detection and compilation” guidance in the ALCops troubleshooting docs, applied to the MCP server’s DevTools resolution order.

[fvet]

Sample project
ALProject17.zip

Goal was to try to read the same 'warnings' from the Problems windows via ALCops MCP

Cursor prompt

use alcops to list all linter warnings

Result

"diagnostics": [
    {
        "id": "AA0228",
        "message": "The local method \u0027UnusedLocalFunction\u0027 is declared but never used.",
        "severity": "Warning",
        "filePath": "c:\\Users\\Frederic.Vercaemst\\Documents\\AL\\ALProject17\\CustomerListExt.Pag-Ext.al",
        "startLine": 13,
        "startColumn": 21,
        "endLine": 13,
        "endColumn": 40,
        "copName": "CodeCop",
        "hasCodeFix": true
    },
    {
        "id": "AD0001",
        "message": "Analyzer \u0027ALCops.LinterCop.Analyzers.InternalProcedureNotReferenced\u0027 threw an exception of type \u0027System.MissingMethodException\u0027 with message \u0027System.MissingMethodException: Method not found: \u0027System.String Microsoft.Dynamics.Nav.CodeAnalysis.Utilities.StringExtensions.QuoteIdentifierIfNeeded(System.String)\u0027.\r\n   at ALCops.LinterCop.Analyzers.InternalProcedureNotReferenced.MethodSymbolAnalyzer.ReportUnchangedReferencePassedParameters(Action\u00601 action)\r\n   at ALCops.LinterCop.Analyzers.InternalProcedureNotReferenced.MethodSymbolAnalyzer.ReportUnchangedReferencePassedParameters(Action\u00601 action)\r\n   at ALCops.LinterCop.Analyzers.InternalProcedureNotReferenced.CheckApplicationObjects(CompilationAnalysisContext compilationAnalysisContext)\r\n   at Microsoft.Dynamics.Nav.CodeAnalysis.Diagnostics.AnalyzerExecutor.\u003C\u003Ec__DisplayClass49_1.\u003CExecuteCompilationActionsCore\u003Eb__0() in X:\\source\\Prod\\Microsoft.Dynamics.Nav.CodeAnalysis\\DiagnosticAnalyzer\\AnalyzerExecutor.cs:line 625\r\n   at Microsoft.Dynamics.Nav.CodeAnalysis.Diagnostics.AnalyzerExecutor.ExecuteAndCatchIfThrows_NoLock(DiagnosticAnalyzer analyzer, Action analyze, Nullable\u00601 info) in X:\\source\\Prod\\Microsoft.Dynamics.Nav.CodeAnalysis\\DiagnosticAnalyzer\\AnalyzerExecutor.cs:line 1088\u0027",
        "severity": "Warning",
        "filePath": "",
        "startLine": 1,
        "startColumn": 1,
        "endLine": 1,
        "endColumn": 1,
        "copName": "Unknown",
        "hasCodeFix": false
    }
],
"warnings": null
}

Seems like AD0001 blocks the MCP from continuing and returning LC0052 (cfr. Problems window)

[Arthurvdv]

@fvet, Thanks for your help here! I believe I've resolved this with the release of version 0.1.0-alpha.8 of the ALCops MCP.

Can you give this a try and see if it's working as expected?