1.1.4 Core Diagnostics

🧩 RDCore.Diagnostics is the core platform extension responsible for issuing all language core diagnostics. Additional first-party or third-party extensions may provide additional or advanced diagnostics to the LSP orchestration layer.

A diagnostics provider is a platform extension whose manifest advertises the DiagnoseDocument capability. RDCore.Diagnostics is the core-bundled diagnostics provider; see RD-VBAL §2.6.5 Diagnostics Pipeline.

🧩 The role of analyzers in extensions like RDCore.Diagnostics is to inspect the flags and errors in semantic contexts, and issue diagnostics. Semantic flags are described in RD-VBAL §1.1.3 Core Semantic Flags.

Diagnostic Codes

The schema of a diagnostic is specified by LSP 3.17 § Diagnostic. It includes a Code, whose format the RDCore platform specifies as follows:

Format	Description	See
`VBC00000`	Visual Basic Compilation error diagnostics	RD-VBAL §2.6.1 Syntax Errors, RD-VBAL §2.6.2 Semantic Compilation Errors
`VBR00000`	Visual Basic Runtime error diagnostics	RD-VBAL §2.6.3 Runtime Errors
`VBA00000`	Visual Basic Application error diagnostics	RD-VBAL §2.6.3 Runtime Errors
`RDC00000`	RDCore core diagnostics	RD-VBAL §2.6.4 Rubberduck Core Diagnostics
`RDX00000`	RDCore extension diagnostics	The documentation pertaining to the extension

🎯 Every RDCore LSP diagnostic carries a stable code. See RD-VBAL §2.6 Diagnostics.

Numeric Portion

The 00000 numeric portion of a diagnostic code is a five-digit zero-padded code, e.g. VBC00001, VBR00009, RDC01001. Its value depends on the nature of the diagnostic:

Origin	Diagnostic	Numeric portion
The parser	Normally a syntax error	A VBCompileErrorId value between 42 and 999.
The static semantics analysis pass	A compilation error	A `VBCompileErrorId` value greater than or equal to 9300.
A language core extension	A compilation error	A `VBCompileErrorId` value between 8000 and 9299.
The runtime semantics analysis pass	A runtime error	A VBRuntimeErrorId value corresponding to its MS-VBAL specified error code.
Workspace source code	An error raised by the workspace program	An unspecified `VBA00000` code, defined by the custom error code raised in the workspace program.
RDCore.Diagnostics	Any other language core diagnostic	Documented under an `RDC00000` code.
Any other first-party extension	A platform extension diagnostic	Shall be documented under an `RDX00000` code, in the documentation pertaining to that extension.
A third-party extension	A platform extension diagnostic	May be reported under an available `RDX` code, or under a reasonably publisher-specific 3-letter prefix.

Diagnostics contributed by other extensions must use their own prefix, distinct from RDC. This keeps codes unique and traceable to their source.

Warning

A third-party extension that issues already-documented first-party diagnostic codes may be required to modify its codes before it can be distributed through the platform's official distribution channels. This ensures that all diagnostic codes published under the platform remain traceable and searchable online.

Run-time and Application Errors

A clean separation of application-defined errors from specified semantic runtime errors is compliant with MS-VBAL. The MS-VBA implementation weakly separates them using the vbObjectError constant. The proper use of this constant has historically been misunderstood, and MS-VBA makes no effective distinction between run-time errors and application errors.

RDCore removes the need for the vbObjectError constant by internally representing run-time errors and application errors as different error metadata types: VBRuntimeErrorInfo and VBApplicationErrorInfo. This clarifies their origin before they reach the runtime.

Error Descriptions

The description of a compilation or run-time error shall be identical to the corresponding MS-VBA description.

All RD-VBA trace messages can include an optional verbose message. The platform shall use this verbose message to further explain the reason behind any error being raised. The verbose message is independent of, or supplemental to, any other verbose content, including but not limited to execution stack traces.