Final answer:
Type checking is an important part of the static semantics of the if statement to ensure compatible types are used in the expressions. If the types are not compatible, a type error will occur during compilation.
Step-by-step explanation:
In the static semantics of the if statement, type checking is a crucial part. Type checking ensures that the expressions e1, e2, and e3 in the if statement are of compatible types.
For example, if e1 is a boolean expression, then e2 and e3 must have compatible types, such as both being integers.
If the types are not compatible, a type error will occur during compilation, indicating that the if statement may not be correctly written.