invalid argument to built-in function

error

verifiedverified on v3.7.0 categorystdlib terminalstable code

What it means

Native functions validate their inputs and report failures with a module-prefixed message (`math:`, `json:`, `fs:`, `db:`, `http:`, `web:`, `template:`). The classifier maps those prefixes to this code.

Trigger condition

A built-in or native-module function received an invalid argument — wrong type, out-of-domain value, malformed input.

Minimal failing example

import math
echo(string(math.factorial(-1)))

Verified fix

(validate the argument before calling the function)

Check the function's documented domain before calling; validate inputs.

What the interpreter prints

error[STDLIB001]: invalid argument to built-in function
  --> app.mz:1:16
 1 | import math
   |                 ^
   |
reason: (the exact problem, with positions)
help:   (a suggested fix appears here)
docs:   https://crossberry-in.github.io/mozhi-doc/errors/STDLIB001

Run mozhi --json run app.mz to get the same information as machine-readable JSON (schema mozhi.diagnostics.v1), or --verbose to also show grouped related diagnostics. See the CLI reference.

Suggested fix

Read the `reason` text — it names the module and the specific problem. Guard inputs with conditions before the call.

Related syntax

Standard library

Related diagnostics

RUNTIME001

Reference links

Limitations

These errors carry no source span (the AST node is not available inside built-ins); the message and docs link are still complete.