replace-parameter-not-found

Id

@azure-tools/typespec-client-generator-core/replace-parameter-not-found

Severity: error

This diagnostic is issued when replaceParameter is called with a selector that does not match any parameter on the operation.

Impact

• Area: Client customization transformations. Blocks replaceParameter from producing the intended customized signature because the selector does not match an operation parameter.
• Not affected: The original operation signature is unchanged.

❌ Incorrect Usage

@service
namespace MyService {
  op myOp(existingParam: string): void;
}

model NewParams {
  replacement: int32;
}
alias Modified = replaceParameter(MyService.myOp, "missingParam", NewParams.replacement); // `missingParam` is not a parameter of `myOp`

Diagnostic Message

TCGC reports:

Parameter "missingParam" not found in operation "myOp".

✅ How to Fix

Use the exact name or model property reference for an existing operation parameter.

@service
namespace MyService {
  op myOp(existingParam: string): void;
}

model NewParams {
  replacement: int32;
}
alias Modified = replaceParameter(MyService.myOp, "existingParam", NewParams.replacement);