Where is Haskell's or GHC's main defined?

Question

In Haskell, the execution of a compiled program starts with executing main in module Main . This function must be of type IO () .

Which standard or reference defines the above?

Haskell 2010 and Haskell 98 don't define main formally (although there are several examples of functions called main ), instead saying:

We leave as implementation dependent the ways in which Haskell programs are to be manipulated, interpreted, compiled, etc.

GHC User's Guide instructs the user to create a main function but never mentions its required type or that it is the start of the program execution. There are references to the Main module but not main function.

Compare C++ (references C11 standard (ISO/IEC 9899:2011) 5.1.2.2.1 Program startup (p: 13)):

Every C program [...] contains the definition [...] of a function called main, which is the designated start of the program .

Which standard or reference says that main is the start of execution of a Haskell program?

Answer 1

A Haskell program is a collection of modules, one of which, by convention, must be called Main and must export the value main . The value of the program is the value of the identifier main in module Main , which must be a computation of type IO τ for some type τ (see Chapter 7 ). When the program is executed, the computation main is performed, and its result (of type τ ) is discarded.

https://www.haskell.org/onlinereport/haskell2010/haskellch5.html#dx11-98001