The `irdl.base` op represent an attribute constraint that will check
that the
base of a type or attribute is the expected one (e.g. `IntegerType`) .
Example:
```mlir
irdl.dialect @cmath {
irdl.type @complex {
%0 = irdl.base "!builtin.integer"
irdl.parameters(%0)
}
irdl.type @complex_wrapper {
%0 = irdl.base @complex
irdl.parameters(%0)
}
}
```
The above program defines a `cmath.complex` type that expects a single
parameter, which is a type with base name `builtin.integer`, which is
the
name of an `IntegerType` type.
It also defines a `cmath.complex_wrapper` type that expects a single
parameter, which is a type of base type `cmath.complex`.