Error during generation of a program - see long text

What causes this issue?

You are trying to generate a temporary program. This program contains
syntax errors.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

Note for SAP Support: The source code has been stored in program &V1&.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.