RakuAST: change semantics of 2ast methods a bit

Previously, the match object was supposed to contain an .ast value
(a RakuAST::Name object).  If this is not present, now it will
create a RakuAST::Name object for it using the stringification of
the match object.

src/Raku/Actions.nqp

@@ -1606,7 +1606,7 @@ class Raku::Actions is HLL::Actions does Raku::CommonActions {
 
     method term:sym<identifier>($/) {
         self.attach: $/, Nodify('Call', 'Name').new:
-          name => Nodify('Name').from-identifier(~$<identifier>),
+          name => $<identifier>.core2ast,
           args => $<args>.ast
     }
 
@@ -2252,8 +2252,8 @@ class Raku::Actions is HLL::Actions does Raku::CommonActions {
         # TODO: <variable> being defined means we should throw an NYI
         # Need to support anonymous enums
         my $name := $<longname>
-                        ?? $<longname>.ast
-                        !! Nodify('Name').from-identifier('');
+          ?? $<longname>.ast
+          !! Nodify('Name').from-identifier('');
         my $base-type := $*OFTYPE ?? $*OFTYPE.ast !! Nodify("Type");
         my $decl := Nodify('Type', 'Enum').new(
             :name($name),
@@ -2752,8 +2752,8 @@ class Raku::Actions is HLL::Actions does Raku::CommonActions {
 
     method typename($/) {
         my $base-name := $<longname>
-            ?? $<longname>.ast
-            !! Nodify('Name').from-identifier('::?' ~ $<identifier>);
+          ?? $<longname>.ast
+          !! Nodify('Name').from-identifier('::?' ~ $<identifier>);
         for $<colonpair> {
             $base-name.add-colonpair($_.ast);
         }

src/Raku/Grammar.nqp

@@ -939,16 +939,21 @@ grammar Raku::Grammar is HLL::Grammar does Raku::Common {
     token use-use     { use     }
 
     # Convert the invocant, a match that is expected to have a RakuAST::Name
-    # object as its ".ast", to a RakuAST::Name object with the name of the
-    # the core functionality if there is an original name known.  Otherwise
-    # it should just return the ".ast" of the invocant.
-    method core2ast() { self.ast }
+    # object as its ".ast" (or to have no ".ast" at all), to a RakuAST::Name
+    # object with the name of the core functionality if there is an original
+    # name known.  Otherwise it should just return the ".ast" of the invocant.
+    method core2ast() {
+        self.ast // self.actions.r('Name').from-identifier(~self)
+    }
 
     # Convert the invocant, a match that is expected to have a RakuAST::Name
-    # object as its ".ast", to a RakuAST::Name object with the name of the
-    # the trait_mod:<is> name if there is an original name known for it.
-    # Otherwise it should just return the ".ast" of the invocant.
-    method trait-is2ast() { self.ast }
+    # object as its ".ast" (or to have no ".ast" at all), to a RakuAST::Name
+    # object with the name of the trait_mod:<is> name if there is an
+    # original name known.  Otherwise it should just return the ".ast" ofi
+    # the invocant.
+    method trait-is2ast() {
+        self.ast // self.actions.r('Name').from-identifier(~self)
+    }
 
     # Convert the given postcircumfix adverb if there is an original name
     # for it.  Otherwise it should just return the adverb unchanged.