Add explicit imports for types and fix bugs (JuliaLang#57302)

I was playing with strengthening the semantics around JuliaLang#57290. However,
the particular change I was trying turned out too breaking (I may try a
weaker version of it). Still, there were a number of good changes found
in two categories:

1. We should explicitly import types when defining constructors. This
has been allowed for a long time, but we may want to consider removing
it, especially given the new binding semantics which make it more
confusing as in JuliaLang#57290.

2. There were a couple of places where I don't think it was intended for
generic functions in question not to extend Base.

Author: Keno

src/Compiler.jl

@@ -72,7 +72,7 @@ using Base.Order
 
 import Base: ==, _topmod, append!, convert, copy, copy!, findall, first, get, get!,
     getindex, haskey, in, isempty, isready, iterate, iterate, last, length, max_world,
-    min_world, popfirst!, push!, resize!, setindex!, size
+    min_world, popfirst!, push!, resize!, setindex!, size, intersect
 
 const getproperty = Core.getfield
 const setproperty! = Core.setfield!