Avoid duplicates in the SSC xrefs.
[mono.git] / mono / metadata / class.c
index 5c708747946c37e2f84718fd08e20454b2609805..0500a054c2feed85cfec5bcdb794549026a6ef2f 100644 (file)
@@ -62,7 +62,6 @@ static void setup_generic_array_ifaces (MonoClass *class, MonoClass *iface, Mono
 
 static MonoMethod* mono_class_get_virtual_methods (MonoClass* klass, gpointer *iter);
 static char* mono_assembly_name_from_token (MonoImage *image, guint32 type_token);
-static gboolean mono_class_is_variant_compatible (MonoClass *klass, MonoClass *oklass);
 static void mono_field_resolve_type (MonoClassField *field, MonoError *error);
 static guint32 mono_field_resolve_flags (MonoClassField *field);
 static void mono_class_setup_vtable_full (MonoClass *class, GList *in_setup);
@@ -901,7 +900,16 @@ mono_class_inflate_generic_method_full_checked (MonoMethod *method, MonoClass *k
                method = imethod->declaring;
        }
 
-       if (!method->is_generic && !method->klass->generic_container)
+       /*
+        * A method only needs to be inflated if the context has argument for which it is
+        * parametric. Eg:
+        * 
+        * class Foo<T> { void Bar(); } - doesn't need to be inflated if only mvars' are supplied
+        * class Foo { void Bar<T> (); } - doesn't need to be if only vars' are supplied
+        * 
+        */
+       if (!((method->is_generic && context->method_inst) || 
+               (method->klass->generic_container && context->class_inst)))
                return method;
 
        /*
@@ -1668,10 +1676,16 @@ mono_class_layout_fields (MonoClass *class)
                if (layout != TYPE_ATTRIBUTE_AUTO_LAYOUT)
                        passes = 1;
 
-               if (class->parent)
+               if (class->parent) {
+                       mono_class_setup_fields (class->parent);
+                       if (class->parent->exception_type) {
+                               mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD, NULL);
+                               return;
+                       }
                        real_size = class->parent->instance_size;
-               else
+               } else {
                        real_size = sizeof (MonoObject);
+               }
 
                for (pass = 0; pass < passes; ++pass) {
                        for (i = 0; i < top; i++){
@@ -2392,6 +2406,16 @@ mono_unload_interface_ids (MonoBitSet *bitset)
        mono_loader_unlock ();
 }
 
+void
+mono_unload_interface_id (MonoClass *class)
+{
+       if (class->interface_id) {
+               mono_loader_lock ();
+               mono_bitset_clear (global_interface_bitset, class->interface_id);
+               mono_loader_unlock ();
+       }
+}
+
 /*
  * mono_get_unique_iid:
  * @class: interface
@@ -2422,16 +2446,18 @@ mono_get_unique_iid (MonoClass *class)
        }
        mono_bitset_set (global_interface_bitset, iid);
        /* set the bit also in the per-image set */
-       if (class->image->interface_bitset) {
-               if (iid >= mono_bitset_size (class->image->interface_bitset)) {
-                       MonoBitSet *new_set = mono_bitset_clone (class->image->interface_bitset, iid + 1);
-                       mono_bitset_free (class->image->interface_bitset);
-                       class->image->interface_bitset = new_set;
+       if (!class->generic_class) {
+               if (class->image->interface_bitset) {
+                       if (iid >= mono_bitset_size (class->image->interface_bitset)) {
+                               MonoBitSet *new_set = mono_bitset_clone (class->image->interface_bitset, iid + 1);
+                               mono_bitset_free (class->image->interface_bitset);
+                               class->image->interface_bitset = new_set;
+                       }
+               } else {
+                       class->image->interface_bitset = mono_bitset_new (iid + 1, 0);
                }
-       } else {
-               class->image->interface_bitset = mono_bitset_new (iid + 1, 0);
+               mono_bitset_set (class->image->interface_bitset, iid);
        }
-       mono_bitset_set (class->image->interface_bitset, iid);
 
 #ifndef MONO_SMALL_CONFIG
        if (mono_print_vtable) {
@@ -2539,7 +2565,7 @@ mono_class_interface_offset_with_variance (MonoClass *klass, MonoClass *itf, gbo
                return -1;
 
        for (i = 0; i < klass->interface_offsets_count; i++) {
-               if (mono_class_is_variant_compatible (itf, klass->interfaces_packed [i])) {
+               if (mono_class_is_variant_compatible (itf, klass->interfaces_packed [i], FALSE)) {
                        *non_exact_match = TRUE;
                        return klass->interface_offsets_packed [i];
                }
@@ -3525,6 +3551,18 @@ print_method_signatures (MonoMethod *im, MonoMethod *cm) {
 }
 
 #endif
+static gboolean
+is_wcf_hack_disabled (void)
+{
+       static gboolean disabled;
+       static gboolean inited = FALSE;
+       if (!inited) {
+               disabled = g_getenv ("MONO_DISABLE_WCF_HACK") != NULL;
+               inited = TRUE;
+       }
+       return disabled;
+}
+
 static gboolean
 check_interface_method_override (MonoClass *class, MonoMethod *im, MonoMethod *cm, gboolean require_newslot, gboolean interface_is_explicitly_implemented_by_class, gboolean slot_is_empty, gboolean security_enabled) {
        MonoMethodSignature *cmsig, *imsig;
@@ -3569,6 +3607,15 @@ check_interface_method_override (MonoClass *class, MonoMethod *im, MonoMethod *c
                if (mono_security_get_mode () == MONO_SECURITY_MODE_CORE_CLR)
                        mono_security_core_clr_check_override (class, cm, im);
                TRACE_INTERFACE_VTABLE (printf ("[NAME CHECK OK]"));
+               if (is_wcf_hack_disabled () && !mono_method_can_access_method_full (cm, im, NULL)) {
+                       char *body_name = mono_method_full_name (cm, TRUE);
+                       char *decl_name = mono_method_full_name (im, TRUE);
+                       mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD, g_strdup_printf ("Method %s overrides method '%s' which is not accessible", body_name, decl_name));
+                       g_free (body_name);
+                       g_free (decl_name);
+                       return FALSE;
+               }
+
                return TRUE;
        } else {
                MonoClass *ic = im->klass;
@@ -3646,6 +3693,15 @@ check_interface_method_override (MonoClass *class, MonoMethod *im, MonoMethod *c
                        mono_security_core_clr_check_override (class, cm, im);
                
                TRACE_INTERFACE_VTABLE (printf ("[INJECTED INTERFACE CHECK OK]"));
+               if (is_wcf_hack_disabled () && !mono_method_can_access_method_full (cm, im, NULL)) {
+                       char *body_name = mono_method_full_name (cm, TRUE);
+                       char *decl_name = mono_method_full_name (im, TRUE);
+                       mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD, g_strdup_printf ("Method %s overrides method '%s' which is not accessible", body_name, decl_name));
+                       g_free (body_name);
+                       g_free (decl_name);
+                       return FALSE;
+               }
+               
                return TRUE;
        }
 }
@@ -3692,12 +3748,11 @@ print_vtable_full (MonoClass *class, MonoMethod** vtable, int size, int first_no
        }
        for (i = 0; i < size; ++i) {
                MonoMethod *cm = vtable [i];
-               if (cm) {
-                       char *cm_name = mono_method_full_name (cm, TRUE);
-                       char newness = (i < parent_size) ? 'O' : ((i < first_non_interface_slot) ? 'I' : 'N');
-                       printf ("  [%c][%03d][INDEX %03d] %s\n", newness, i, cm->slot, cm_name);
-                       g_free (cm_name);
-               }
+               char *cm_name = cm ? mono_method_full_name (cm, TRUE) : g_strdup ("nil");
+               char newness = (i < parent_size) ? 'O' : ((i < first_non_interface_slot) ? 'I' : 'N');
+
+               printf ("  [%c][%03d][INDEX %03d] %s [%p]\n", newness, i, cm ? cm->slot : - 1, cm_name, cm);
+               g_free (cm_name);
        }
 
        g_free (full_name);
@@ -3790,6 +3845,14 @@ print_unimplemented_interface_method_info (MonoClass *class, MonoClass *ic, Mono
        }
 }
 
+static MonoMethod*
+mono_method_get_method_definition (MonoMethod *method)
+{
+       while (method->is_inflated)
+               method = ((MonoMethodInflated*)method)->declaring;
+       return method;
+}
+
 static gboolean
 verify_class_overrides (MonoClass *class, MonoMethod **overrides, int onum)
 {
@@ -3824,6 +3887,18 @@ verify_class_overrides (MonoClass *class, MonoMethod **overrides, int onum)
                        mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD, g_strdup ("Method overrides a class or interface that extended or implemented by this type"));
                        return FALSE;
                }
+
+               body = mono_method_get_method_definition (body);
+               decl = mono_method_get_method_definition (decl);
+
+               if (is_wcf_hack_disabled () && !mono_method_can_access_method_full (body, decl, NULL)) {
+                       char *body_name = mono_method_full_name (body, TRUE);
+                       char *decl_name = mono_method_full_name (decl, TRUE);
+                       mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD, g_strdup_printf ("Method %s overrides method '%s' which is not accessible", body_name, decl_name));
+                       g_free (body_name);
+                       g_free (decl_name);
+                       return FALSE;
+               }
        }
        return TRUE;
 }
@@ -4079,6 +4154,8 @@ mono_class_setup_vtable_general (MonoClass *class, MonoMethod **overrides, int o
                        if (im->flags & METHOD_ATTRIBUTE_STATIC)
                                continue;
 
+                       TRACE_INTERFACE_VTABLE (printf ("\tchecking iface method %s\n", mono_method_full_name (im,1)));
+
                        // If there is an explicit implementation, just use it right away,
                        // otherwise look for a matching method
                        if (override_im == NULL) {
@@ -4203,9 +4280,21 @@ mono_class_setup_vtable_general (MonoClass *class, MonoMethod **overrides, int o
                                                if (slot == -1)
                                                        goto fail;
 
+                                               if (is_wcf_hack_disabled () && !mono_method_can_access_method_full (cm, m1, NULL)) {
+                                                       char *body_name = mono_method_full_name (cm, TRUE);
+                                                       char *decl_name = mono_method_full_name (m1, TRUE);
+                                                       mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD, g_strdup_printf ("Method %s overrides method '%s' which is not accessible", body_name, decl_name));
+                                                       g_free (body_name);
+                                                       g_free (decl_name);
+                                                       goto fail;
+                                               }
+
                                                g_assert (cm->slot < max_vtsize);
                                                if (!override_map)
                                                        override_map = g_hash_table_new (mono_aligned_addr_hash, NULL);
+                                               TRACE_INTERFACE_VTABLE (printf ("adding iface override from %s [%p] to %s [%p]\n",
+                                                       mono_method_full_name (m1, 1), m1,
+                                                       mono_method_full_name (cm, 1), cm));
                                                g_hash_table_insert (override_map, m1, cm);
                                                break;
                                        }
@@ -4240,6 +4329,9 @@ mono_class_setup_vtable_general (MonoClass *class, MonoMethod **overrides, int o
                        overrides [i * 2 + 1]->slot = decl->slot;
                        if (!override_map)
                                override_map = g_hash_table_new (mono_aligned_addr_hash, NULL);
+                       TRACE_INTERFACE_VTABLE (printf ("adding explicit override from %s [%p] to %s [%p]\n", 
+                               mono_method_full_name (decl, 1), decl,
+                               mono_method_full_name (overrides [i * 2 + 1], 1), overrides [i * 2 + 1]));
                        g_hash_table_insert (override_map, decl, overrides [i * 2 + 1]);
 
                        if (mono_security_get_mode () == MONO_SECURITY_MODE_CORE_CLR)
@@ -4252,9 +4344,13 @@ mono_class_setup_vtable_general (MonoClass *class, MonoMethod **overrides, int o
         * overriden, then change the other occurances too.
         */
        if (override_map) {
+               MonoMethod *cm;
+
                for (i = 0; i < max_vtsize; ++i)
                        if (vtable [i]) {
-                               MonoMethod *cm = g_hash_table_lookup (override_map, vtable [i]);
+                               TRACE_INTERFACE_VTABLE (printf ("checking slot %d method %s[%p] for overrides\n", i, mono_method_full_name (vtable [i], 1), vtable [i]));
+
+                               cm = g_hash_table_lookup (override_map, vtable [i]);
                                if (cm)
                                        vtable [i] = cm;
                        }
@@ -5626,40 +5722,65 @@ make_generic_param_class (MonoGenericParam *param, MonoImage *image, gboolean is
 }
 
 #define FAST_CACHE_SIZE 16
-static MonoClass *var_cache_fast [FAST_CACHE_SIZE];
-static MonoClass *mvar_cache_fast [FAST_CACHE_SIZE];
-static GHashTable *var_cache_slow;
-static GHashTable *mvar_cache_slow;
 
 static MonoClass *
 get_anon_gparam_class (MonoGenericParam *param, gboolean is_mvar)
 {
        int n = mono_generic_param_num (param);
+       MonoImage *image = param->image;
        GHashTable *ht;
 
-       if (n < FAST_CACHE_SIZE)
-               return (is_mvar ? mvar_cache_fast : var_cache_fast) [n];
-       ht = is_mvar ? mvar_cache_slow : var_cache_slow;
-       return ht ? g_hash_table_lookup (ht, GINT_TO_POINTER (n)) : NULL;
+       g_assert (image);
+
+       if (n < FAST_CACHE_SIZE) {
+               if (is_mvar)
+                       return image->mvar_cache_fast ? image->mvar_cache_fast [n] : NULL;
+               else
+                       return image->var_cache_fast ? image->var_cache_fast [n] : NULL;
+       } else {
+               ht = is_mvar ? image->mvar_cache_slow : image->var_cache_slow;
+               return ht ? g_hash_table_lookup (ht, GINT_TO_POINTER (n)) : NULL;
+       }
 }
 
+/*
+ * LOCKING: Acquires the loader lock.
+ */
 static void
 set_anon_gparam_class (MonoGenericParam *param, gboolean is_mvar, MonoClass *klass)
 {
        int n = mono_generic_param_num (param);
+       MonoImage *image = param->image;
        GHashTable *ht;
 
+       g_assert (image);
+
        if (n < FAST_CACHE_SIZE) {
-               (is_mvar ? mvar_cache_fast : var_cache_fast) [n] = klass;
+               if (is_mvar) {
+                       /* No locking needed */
+                       if (!image->mvar_cache_fast)
+                               image->mvar_cache_fast = mono_image_alloc0 (image, sizeof (MonoClass*) * FAST_CACHE_SIZE);
+                       image->mvar_cache_fast [n] = klass;
+               } else {
+                       if (!image->var_cache_fast)
+                               image->var_cache_fast = mono_image_alloc0 (image, sizeof (MonoClass*) * FAST_CACHE_SIZE);
+                       image->var_cache_fast [n] = klass;
+               }
                return;
        }
-       ht = is_mvar ? mvar_cache_slow : var_cache_slow;
+       ht = is_mvar ? image->mvar_cache_slow : image->var_cache_slow;
        if (!ht) {
-               ht = g_hash_table_new (NULL, NULL);
-               if (is_mvar)
-                       mvar_cache_slow = ht;
-               else
-                       var_cache_slow = ht;
+               mono_loader_lock ();
+               ht = is_mvar ? image->mvar_cache_slow : image->var_cache_slow;
+               if (!ht) {
+                       ht = g_hash_table_new (NULL, NULL);
+                       mono_memory_barrier ();
+                       if (is_mvar)
+                               image->mvar_cache_slow = ht;
+                       else
+                               image->var_cache_slow = ht;
+               }
+               mono_loader_unlock ();
        }
 
        g_hash_table_insert (ht, GINT_TO_POINTER (n), klass);
@@ -6362,10 +6483,10 @@ mono_class_get_field_token (MonoClassField *field)
        int i;
 
        mono_class_setup_fields_locking (klass);
-       if (klass->exception_type)
-               return 0;
 
        while (klass) {
+               if (!klass->fields)
+                       return 0;
                for (i = 0; i < klass->field.count; ++i) {
                        if (&klass->fields [i] == field) {
                                int idx = klass->field.first + i + 1;
@@ -6419,7 +6540,9 @@ mono_class_get_field_default_value (MonoClassField *field, MonoTypeEnum *def_typ
                
        if (!klass->ext->field_def_values [field_index].data) {
                cindex = mono_metadata_get_constant_index (field->parent->image, mono_class_get_field_token (field), 0);
-               g_assert (cindex);
+               if (!cindex)
+                       return NULL;
+
                g_assert (!(field->type->attrs & FIELD_ATTRIBUTE_HAS_FIELD_RVA));
 
                mono_metadata_decode_row (&field->parent->image->tables [MONO_TABLE_CONSTANT], cindex - 1, constant_cols, MONO_CONSTANT_SIZE);
@@ -7169,6 +7292,12 @@ mono_class_is_subclass_of (MonoClass *klass, MonoClass *klassc,
        return FALSE;
 }
 
+static gboolean
+mono_type_is_generic_argument (MonoType *type)
+{
+       return type->type == MONO_TYPE_VAR || type->type == MONO_TYPE_MVAR;
+}
+
 gboolean
 mono_class_has_variant_generic_params (MonoClass *klass)
 {
@@ -7187,6 +7316,26 @@ mono_class_has_variant_generic_params (MonoClass *klass)
        return FALSE;
 }
 
+static gboolean
+mono_gparam_is_reference_conversible (MonoClass *target, MonoClass *candidate, gboolean check_for_reference_conv)
+{
+       if (target == candidate)
+               return TRUE;
+
+       if (check_for_reference_conv &&
+               mono_type_is_generic_argument (&target->byval_arg) &&
+               mono_type_is_generic_argument (&candidate->byval_arg)) {
+               MonoGenericParam *gparam = candidate->byval_arg.data.generic_param;
+               MonoGenericParamInfo *pinfo = mono_generic_param_info (gparam);
+
+               if (!pinfo || (pinfo->flags & GENERIC_PARAMETER_ATTRIBUTE_REFERENCE_TYPE_CONSTRAINT) == 0)
+                       return FALSE;
+       }
+       if (!mono_class_is_assignable_from (target, candidate))
+               return FALSE;
+       return TRUE;
+}
+
 /**
  * @container the generic container from the GTD
  * @klass: the class to be assigned to
@@ -7195,14 +7344,17 @@ mono_class_has_variant_generic_params (MonoClass *klass)
  * Both klass and oklass must be instances of the same generic interface.
  * Return true if @klass can be assigned to a @klass variable
  */
-static gboolean
-mono_class_is_variant_compatible (MonoClass *klass, MonoClass *oklass)
+gboolean
+mono_class_is_variant_compatible (MonoClass *klass, MonoClass *oklass, gboolean check_for_reference_conv)
 {
        int j;
        MonoType **klass_argv, **oklass_argv;
        MonoClass *klass_gtd = mono_class_get_generic_type_definition (klass);
        MonoGenericContainer *container = klass_gtd->generic_container;
 
+       if (klass == oklass)
+               return TRUE;
+
        /*Viable candidates are instances of the same generic interface*/
        if (mono_class_get_generic_type_definition (oklass) != klass_gtd || oklass == klass_gtd)
                return FALSE;
@@ -7214,7 +7366,7 @@ mono_class_is_variant_compatible (MonoClass *klass, MonoClass *oklass)
                MonoClass *param1_class = mono_class_from_mono_type (klass_argv [j]);
                MonoClass *param2_class = mono_class_from_mono_type (oklass_argv [j]);
 
-               if (param1_class->valuetype != param2_class->valuetype)
+               if (param1_class->valuetype != param2_class->valuetype || (param1_class->valuetype && param1_class != param2_class))
                        return FALSE;
 
                /*
@@ -7223,10 +7375,10 @@ mono_class_is_variant_compatible (MonoClass *klass, MonoClass *oklass)
                 */
                if (param1_class != param2_class) {
                        if (mono_generic_container_get_param_info (container, j)->flags & MONO_GEN_PARAM_VARIANT) {
-                               if (!mono_class_is_assignable_from (param1_class, param2_class))
+                               if (!mono_gparam_is_reference_conversible (param1_class, param2_class, check_for_reference_conv))
                                        return FALSE;
                        } else if (mono_generic_container_get_param_info (container, j)->flags & MONO_GEN_PARAM_COVARIANT) {
-                               if (!mono_class_is_assignable_from (param2_class, param1_class))
+                               if (!mono_gparam_is_reference_conversible (param2_class, param1_class, check_for_reference_conv))
                                        return FALSE;
                        } else
                                return FALSE;
@@ -7235,6 +7387,107 @@ mono_class_is_variant_compatible (MonoClass *klass, MonoClass *oklass)
        return TRUE;
 }
 
+static gboolean
+mono_gparam_is_assignable_from (MonoClass *target, MonoClass *candidate)
+{
+       MonoGenericParam *gparam, *ogparam;
+       MonoGenericParamInfo *tinfo, *cinfo;
+       MonoClass **candidate_class;
+       gboolean class_constraint_satisfied, valuetype_constraint_satisfied;
+       int tmask, cmask;
+
+       if (target == candidate)
+               return TRUE;
+       if (target->byval_arg.type != candidate->byval_arg.type)
+               return FALSE;
+
+       gparam = target->byval_arg.data.generic_param;
+       ogparam = candidate->byval_arg.data.generic_param;
+       tinfo = mono_generic_param_info (gparam);
+       cinfo = mono_generic_param_info (ogparam);
+
+       class_constraint_satisfied = FALSE;
+       valuetype_constraint_satisfied = FALSE;
+
+       /*candidate must have a super set of target's special constraints*/
+       tmask = tinfo->flags & GENERIC_PARAMETER_ATTRIBUTE_SPECIAL_CONSTRAINTS_MASK;
+       cmask = cinfo->flags & GENERIC_PARAMETER_ATTRIBUTE_SPECIAL_CONSTRAINTS_MASK;
+
+       if (cinfo->constraints) {
+               for (candidate_class = cinfo->constraints; *candidate_class; ++candidate_class) {
+                       MonoClass *cc = *candidate_class;
+
+                       if (mono_type_is_reference (&cc->byval_arg) && !MONO_CLASS_IS_INTERFACE (cc))
+                               class_constraint_satisfied = TRUE;
+                       else if (!mono_type_is_reference (&cc->byval_arg) && !MONO_CLASS_IS_INTERFACE (cc))
+                               valuetype_constraint_satisfied = TRUE;
+               }
+       }
+       class_constraint_satisfied |= (cmask & GENERIC_PARAMETER_ATTRIBUTE_REFERENCE_TYPE_CONSTRAINT) != 0;
+       valuetype_constraint_satisfied |= (cmask & GENERIC_PARAMETER_ATTRIBUTE_VALUE_TYPE_CONSTRAINT) != 0;
+
+       if ((tmask & GENERIC_PARAMETER_ATTRIBUTE_REFERENCE_TYPE_CONSTRAINT) && !class_constraint_satisfied)
+               return FALSE;
+       if ((tmask & GENERIC_PARAMETER_ATTRIBUTE_VALUE_TYPE_CONSTRAINT) && !valuetype_constraint_satisfied)
+               return FALSE;
+       if ((tmask & GENERIC_PARAMETER_ATTRIBUTE_CONSTRUCTOR_CONSTRAINT) && !((cmask & GENERIC_PARAMETER_ATTRIBUTE_CONSTRUCTOR_CONSTRAINT) ||
+               valuetype_constraint_satisfied)) {
+               return FALSE;
+       }
+
+
+       /*candidate type constraints must be a superset of target's*/
+       if (tinfo->constraints) {
+               MonoClass **target_class;
+               for (target_class = tinfo->constraints; *target_class; ++target_class) {
+                       MonoClass *tc = *target_class;
+
+                       /*
+                        * A constraint from @target might inflate into @candidate itself and in that case we don't need
+                        * check it's constraints since it satisfy the constraint by itself.
+                        */
+                       if (mono_metadata_type_equal (&tc->byval_arg, &candidate->byval_arg))
+                               continue;
+
+                       if (!cinfo->constraints)
+                               return FALSE;
+
+                       for (candidate_class = cinfo->constraints; *candidate_class; ++candidate_class) {
+                               MonoClass *cc = *candidate_class;
+
+                               if (mono_class_is_assignable_from (tc, cc))
+                                       break;
+
+                               /*
+                                * This happens when we have the following:
+                                *
+                                * Bar<K> where K : IFace
+                                * Foo<T, U> where T : U where U : IFace
+                                *      ...
+                                *      Bar<T> <- T here satisfy K constraint transitively through to U's constraint
+                                *
+                                */
+                               if (mono_type_is_generic_argument (&cc->byval_arg)) {
+                                       if (mono_gparam_is_assignable_from (target, cc))
+                                               break;
+                               }
+                       }
+                       if (!*candidate_class)
+                               return FALSE;
+               }
+       }
+
+       /*candidate itself must have a constraint that satisfy target*/
+       if (cinfo->constraints) {
+               for (candidate_class = cinfo->constraints; *candidate_class; ++candidate_class) {
+                       MonoClass *cc = *candidate_class;
+                       if (mono_class_is_assignable_from (target, cc))
+                               return TRUE;
+               }
+       }
+       return FALSE;
+}
+
 /**
  * mono_class_is_assignable_from:
  * @klass: the class to be assigned to
@@ -7256,12 +7509,27 @@ mono_class_is_assignable_from (MonoClass *klass, MonoClass *oklass)
        if (klass->exception_type || oklass->exception_type)
                return FALSE;
 
-       if ((klass->byval_arg.type == MONO_TYPE_VAR) || (klass->byval_arg.type == MONO_TYPE_MVAR))
-               return klass == oklass;
+       if (mono_type_is_generic_argument (&klass->byval_arg)) {
+               if (!mono_type_is_generic_argument (&oklass->byval_arg))
+                       return FALSE;
+               return mono_gparam_is_assignable_from (klass, oklass);
+       }
 
        if (MONO_CLASS_IS_INTERFACE (klass)) {
-               if ((oklass->byval_arg.type == MONO_TYPE_VAR) || (oklass->byval_arg.type == MONO_TYPE_MVAR))
+               if ((oklass->byval_arg.type == MONO_TYPE_VAR) || (oklass->byval_arg.type == MONO_TYPE_MVAR)) {
+                       MonoGenericParam *gparam = oklass->byval_arg.data.generic_param;
+                       MonoClass **constraints = mono_generic_container_get_param_info (gparam->owner, gparam->num)->constraints;
+                       int i;
+
+                       if (constraints) {
+                               for (i = 0; constraints [i]; ++i) {
+                                       if (mono_class_is_assignable_from (klass, constraints [i]))
+                                               return TRUE;
+                               }
+                       }
+
                        return FALSE;
+               }
 
                /* interface_offsets might not be set for dynamic classes */
                if (oklass->ref_info_handle && !oklass->interface_bitmap)
@@ -7289,13 +7557,13 @@ mono_class_is_assignable_from (MonoClass *klass, MonoClass *oklass)
                        for (i = 0; i < oklass->interface_offsets_count; ++i) {
                                MonoClass *iface = oklass->interfaces_packed [i];
 
-                               if (mono_class_is_variant_compatible (klass, iface))
+                               if (mono_class_is_variant_compatible (klass, iface, FALSE))
                                        return TRUE;
                        }
                }
                return FALSE;
        } else if (klass->delegate) {
-               if (mono_class_has_variant_generic_params (klass) && mono_class_is_variant_compatible (klass, oklass))
+               if (mono_class_has_variant_generic_params (klass) && mono_class_is_variant_compatible (klass, oklass, FALSE))
                        return TRUE;
        }else if (klass->rank) {
                MonoClass *eclass, *eoclass;
@@ -7461,10 +7729,10 @@ mono_class_is_assignable_from_slow (MonoClass *target, MonoClass *candidate)
                return mono_class_implement_interface_slow (target, candidate);
 
        if (target->delegate && mono_class_has_variant_generic_params (target))
-               return mono_class_is_variant_compatible (target, candidate);
+               return mono_class_is_variant_compatible (target, candidate, FALSE);
 
        /*FIXME properly handle nullables and arrays */
-
+       /*FIXME properly handle (M)VAR */
        return FALSE;
 }
 
@@ -8997,6 +9265,9 @@ can_access_type (MonoClass *access_klass, MonoClass *member_klass)
 {
        int access_level;
 
+       if (access_klass->image->assembly && access_klass->image->assembly->corlib_internal)
+               return TRUE;
+
        if (access_klass->element_class && !access_klass->enumtype)
                access_klass = access_klass->element_class;
 
@@ -9056,6 +9327,9 @@ static gboolean
 can_access_member (MonoClass *access_klass, MonoClass *member_klass, MonoClass* context_klass, int access_level)
 {
        MonoClass *member_generic_def;
+       if (access_klass->image->assembly && access_klass->image->assembly->corlib_internal)
+               return TRUE;
+
        if (((access_klass->generic_class && access_klass->generic_class->container_class) ||
                                        access_klass->generic_container) && 
                        (member_generic_def = get_generic_definition_class (member_klass))) {