: Hi,
:  
:   class Foo {
:     submethod BUILD() {
:       say 42;
:     }
:   }
:  
:   class Bar is Foo {
:     submethod BUILD() {
:       say 23;
:     }
:   }
:  
:   my Bar $bar .= new;
:  
: I suppose this will output:
:   42
:   23
:  
: S12 says that "submethod[s] [are] called only when a method call is
: dispatched directly to the current class", but the default implementation of
: "new" (as given by Object), calls BUILDALL, which in turn calls all BUILDs, so
: I think both BUILDs are executed. Are they?

Yes.

: S12 says that "[s]ubmethods are for declaring infrastructural methods that
: shouldn't be inherited by subclasses". I read this "shouldn't be inherited" as
: that a submethod definition of the same name in a subclass does not
: overwrite/substitute the definition of the parent class. Correct?

Correct.

:   class A      { submethod blarb() { say 42 } }
:   class B is A { submethod blarb() { say 23 } }
:   B.new.blarb;
:  
: Does this only output "23"? (I think so, as I don't call A::blarb explicitly.
: If I wanted to call A's blarb, I'd have to say "B.new.A::blarb", correct?)

Yes.

Larry