conc_table_lock.patch

diff --git src/Perl6/Metamodel/Concretization.nqp src/Perl6/Metamodel/Concretization.nqp
index a9751eb0a..18287e984 100644
--- src/Perl6/Metamodel/Concretization.nqp
+++ src/Perl6/Metamodel/Concretization.nqp
@@ -3,6 +3,8 @@ role Perl6::Metamodel::Concretization {
     has @!concretizations;
     has %!conc_table;
 
+    my $lock := NQPLock.new;
+
     method add_concretization($obj, $role, $concrete) {
         @!concretizations[+@!concretizations] := [$role, $concrete];
         nqp::scwbdisable();
@@ -38,21 +40,31 @@ role Perl6::Metamodel::Concretization {
     method !rebuild_table() {
         for @!concretizations {
             nqp::scwbdisable();
-            %!conc_table{~nqp::objectid(nqp::decont($_[0]))} := nqp::decont($_[1]);
+            $lock.protect: {
+                %!conc_table{~nqp::objectid(nqp::decont($_[0]))} := nqp::decont($_[1]);
+            };
             nqp::scwbenable();
         }
     }
 
     # Returns a list where the first element is the number of roles found and the rest are actual type objects.
     method concretization_lookup($obj, $ptype, :$local = 0, :$transitive = 1, :$relaxed = 0) {
-        self.'!rebuild_table'() if nqp::elems(%!conc_table) < nqp::elems(@!concretizations);
-        return [0] unless !$local || $transitive || nqp::elems(%!conc_table);
+        my int $conc_table_elems;
+        $lock.protect: {
+            $conc_table_elems := nqp::elems(%!conc_table);
+        };
+        self.'!rebuild_table'() if $conc_table_elems < nqp::elems(@!concretizations);
+        return [0] unless !$local || $transitive || $conc_table_elems;
         $ptype := nqp::decont($ptype);
         my $id := ~nqp::objectid($ptype);
         my @result;
-        if nqp::existskey(%!conc_table, $id) {
-            return [1, %!conc_table{$id}];
-        }
+        my $return_id;
+        $lock.protect: {
+            if nqp::existskey(%!conc_table, $id) {
+                $return_id := %!conc_table{$id};
+            }
+        };
+        return [1, $return_id] if $return_id;
         if $relaxed {
             # Try search by role group for curryings. The first match is ok. Used by FQN method calls.
             @result[0] := 0;

mro_test_fail.log

[dan@alexandria rakudo]$ ./rakudo-m -I lib/ t/spec/S12-class/mro-6e.t
1..1
# Subtest: Rolified MRO
    1..10
    not ok 1 - basic mro with roles
    # Failed test 'basic mro with roles'
    # at t/spec/S12-class/mro-6e.t line 48
    # at position 2:
    # expected: Nil of Perl6::Metamodel::ClassHOW
    #      got: R2a of Perl6::Metamodel::ConcreteRoleHOW
    not ok 2 - basic mro with parameterized roles
    # Failed test 'basic mro with parameterized roles'
    # at t/spec/S12-class/mro-6e.t line 57
    # at position 2:
    # expected: Nil of Perl6::Metamodel::ClassHOW
    #      got: R2a of Perl6::Metamodel::ConcreteRoleHOW
    not ok 3 - mro with roles: parent on a role
    # Failed test 'mro with roles: parent on a role'
    # at t/spec/S12-class/mro-6e.t line 65
    # at position 2:
    # expected: Nil of Perl6::Metamodel::ClassHOW
    #      got: R2a of Perl6::Metamodel::ConcreteRoleHOW
    ok 4 - mro with roles: hiding a class hides its roles
    not ok 5 - mro with roles: .^mro method ignores hiding
    # Failed test 'mro with roles: .^mro method ignores hiding'
    # at t/spec/S12-class/mro-6e.t line 74
    # at position 2:
    # expected: Nil of Perl6::Metamodel::ClassHOW
    #      got: R2a of Perl6::Metamodel::ConcreteRoleHOW
    ok 6 - mro with roles: puned 'is hidden' role hides its roles too
    ok 7 - mro with roles: puned parameterized 'is hidden' role hides its roles too
    ok 8 - mro with roles: 'hides' on a role hides its roles too
    ok 9 - mro with roles: 'hides' on a parameterized role hides its roles too
    not ok 10 - mro with roles: 'hides' used with a role is preserved
    # Failed test 'mro with roles: 'hides' used with a role is preserved'
    # at t/spec/S12-class/mro-6e.t line 121
    # at position 1:
    # expected: Nil of Perl6::Metamodel::ClassHOW
    #      got: R3a of Perl6::Metamodel::ConcreteRoleHOW
    # You failed 5 tests of 10
not ok 1 - Rolified MRO
# Failed test 'Rolified MRO'
# at t/spec/S12-class/mro-6e.t line 40
# You failed 1 test of 1