What are the common pitfalls used for the Data-types? - FORTRAN

What are the common pitfalls used for the Data-types?

- Data-types use the implicit variable declarations that make it sometime error prone and allow more time to be put on to correct the problems.

- Non-intrinsic functions are used without the use of type declarations and it also has the incompatible argument list.

- It has incompatible declarations that are used in the block using the constants and parameters.

- It provides the untyped integer information that assumes that it is typed properly and the functions are used correctly.