Official Description
6.9.1 On reading an integer from a text file, it is an error if the value of the signed-integer read is not assignment-compatible with the type possessed by the variable-access.
Simplified Description
In other words, it is an error to read an integer value from a text file into a variable, if the integer value is not assignment-compatible with the type possessed by the variable.
Error Handling
This error is reported if range checking is enabled.