change X::Comp to mean "potentially compile-time"

There are some cases (like trait application and quasi unsplicing)
that usually happen at compile time, but not always.
When they were thrown at run time, they warned, because
file name and line number were Any. This is now fixed.

src/Perl6/World.pm

@@ -1916,6 +1916,7 @@ class Perl6::World is HLL::World {
         if $type_found {
             %opts<line>    := HLL::Compiler.lineof($/.orig, $/.from);
             %opts<modules> := p6ize_recursive(@*MODULES);
+            %opts<is-compile-time> := 1;
             for %opts -> $p {
                 if pir::does($p.value, 'array') {
                     my @a := [];

src/core/Exception.pm

@@ -55,6 +55,8 @@ my class Exception {
         $return($fail) unless nqp::isnull($return);
         $fail
     }
+
+    method is-compile-time { False }
 }
 
 my class X::AdHoc is Exception {
@@ -154,7 +156,7 @@ do {
             my $e := EXCEPTION($ex);
             my Mu $err := pir::getstderr__P();
 
-            if X::Comp.ACCEPTS($e) || is_runtime($ex.backtrace) {
+            if $e.is-compile-time || is_runtime($ex.backtrace) {
                 $err.print: $e.gist;
                 $err.print: "\n";
             }
@@ -304,23 +306,32 @@ my role X::Comp is Exception {
     has $.line;
     has $.column;
     has @.modules;
+    has $.is-compile-time = False;
     multi method gist(::?CLASS:D:) {
-        my $r = "===SORRY!===\n$.message\nat $.filename():$.line";
-        for @.modules.reverse[1..*] {
-            $r ~= $_<module>.defined
-                    ?? "\n  from module $_<module> ($_<filename>:$_<line>)"
-                    !! "\n  from $_<filename>:$_<line>";
+        if $.is-compile-time {
+            my $r = "===SORRY!===\n$.message\nat $.filename():$.line";
+            for @.modules.reverse[1..*] {
+                $r ~= $_<module>.defined
+                        ?? "\n  from module $_<module> ($_<filename>:$_<line>)"
+                        !! "\n  from $_<filename>:$_<line>";
+            }
+            $r;
+        }
+        else {
+            self.Exception::gist;
         }
-        $r;
     }
     method SET_FILE_LINE($file, $line) {
         $!filename = $file;
         $!line     = $line;
+        $!is-compile-time = True;
     }
 }
 
 # XXX a hack for getting line numbers from exceptions from the metamodel
-my class X::Comp::AdHoc is X::AdHoc does X::Comp { }
+my class X::Comp::AdHoc is X::AdHoc does X::Comp {
+    method is-compile-time() { True }
+}
 
 my role X::Syntax does X::Comp { }
 my role X::Pod                 { }