diff --git a/examples/type_metadata/generated/meta_types.c b/examples/type_metadata/generated/meta_types.c
index f49ad16..67ac7c7 100644
--- a/examples/type_metadata/generated/meta_types.c
+++ b/examples/type_metadata/generated/meta_types.c
@@ -1,22 +1,81 @@
-// generated by W:/metadesk/examples/type_metadata/type_metadata.c:949
-TypeInfoMember MagicalPoint2D_members[0] = {
+// generated by W:/metadesk/examples/type_metadata/type_metadata.c:993
+TypeInfoMember Circle_members[2] = {
+{"r", 1, -1, &F32_type_info},
+{"pos", 3, -1, &V2F32_type_info},
 };
-TypeInfoMember BackwardsArray_members[2] = {
-{"vals", 4, -1, &U32_type_info},
+TypeInfoMember RoundedSegment_members[3] = {
+{"r", 1, -1, &F32_type_info},
+{"p1", 2, -1, &V2F32_type_info},
+{"p2", 2, -1, &V2F32_type_info},
+};
+TypeInfoMember RoundedPolygon_members[3] = {
+{"r", 1, -1, &F32_type_info},
 {"count", 5, -1, &U32_type_info},
-};
-TypeInfoMember TwinType_members[1] = {
-{"val", 3, -1, &U32_type_info},
+{"p", 1, 1, &V2F32_type_info},
 };
 
-// generated by W:/metadesk/examples/type_metadata/type_metadata.c:988
+// generated by W:/metadesk/examples/type_metadata/type_metadata.c:1032
+TypeInfoEnumerant Shape_members[3] = {
+{"Circle", 6, 1},
+{"Segment", 7, 2},
+{"Polygon", 7, 3},
+};
 
-// generated by W:/metadesk/examples/type_metadata/type_metadata.c:1024
+// generated by W:/metadesk/examples/type_metadata/type_metadata.c:1068
 TypeInfo U32_type_info = {TypeKind_Basic, "U32", 3, 4, 0, 0};
-TypeInfo MagicalPoint2D_type_info = {TypeKind_Struct, "MagicalPoint2D", 14, 0, MagicalPoint2D_members, 0};
-TypeInfo BackwardsArray_type_info = {TypeKind_Struct, "BackwardsArray", 14, 2, BackwardsArray_members, 0};
-TypeInfo TwinType_type_info = {TypeKind_Basic, "TwinType", 8, 4, 0, 0};
-TypeInfo TwinType_type_info = {TypeKind_Struct, "TwinType", 8, 1, TwinType_members, 0};
+TypeInfo F32_type_info = {TypeKind_Basic, "F32", 3, 4, 0, 0};
+TypeInfo V2F32_type_info = {TypeKind_Basic, "V2F32", 5, 8, 0, 0};
+TypeInfo Circle_type_info = {TypeKind_Struct, "Circle", 6, 2, Circle_members, 0};
+TypeInfo RoundedSegment_type_info = {TypeKind_Struct, "RoundedSegment", 14, 3, RoundedSegment_members, 0};
+TypeInfo RoundedPolygon_type_info = {TypeKind_Struct, "RoundedPolygon", 14, 3, RoundedPolygon_members, 0};
+TypeInfo Shape_type_info = {TypeKind_Enum, "Shape", 5, 3, Shape_members, &U32_type_info};
 
-// generated by W:/metadesk/examples/type_metadata/type_metadata.c:1084
+// generated by W:/metadesk/examples/type_metadata/type_metadata.c:1128
+TypeInfo*
+type_info_from_shape(Shape v)
+{
+TypeInfo* result;
+switch (v)
+{
+default:
+{
+result = 0;
+}break;
+case Shape_Circle:
+{
+result = &Circle_type_info;
+}break;
+case Shape_Segment:
+{
+result = &RoundedSegment_type_info;
+}break;
+case Shape_Polygon:
+{
+result = &RoundedPolygon_type_info;
+}break;
+}
+return(result);
+}
+U32
+max_slot_from_shape(Shape v)
+{
+U32 result;
+switch (v)
+{
+default:
+{
+result = 0;
+}break;
+case Shape_Circle:
+case Shape_Segment:
+{
+result = 64;
+}break;
+case Shape_Polygon:
+{
+result = 12;
+}break;
+}
+return(result);
+}
 
diff --git a/examples/type_metadata/generated/meta_types.h b/examples/type_metadata/generated/meta_types.h
index 665118f..8251a53 100644
--- a/examples/type_metadata/generated/meta_types.h
+++ b/examples/type_metadata/generated/meta_types.h
@@ -1,29 +1,45 @@
 #if !defined(META_TYPES_H)
 #define META_TYPES_H
-// generated by W:/metadesk/examples/type_metadata/type_metadata.c:826
-typedef struct MagicalPoint2D MagicalPoint2D;
-struct MagicalPoint2D
+// generated by W:/metadesk/examples/type_metadata/type_metadata.c:870
+typedef struct Circle Circle;
+struct Circle
 {
+F32 r;
+V2F32 pos;
 };
-typedef struct BackwardsArray BackwardsArray;
-struct BackwardsArray
+typedef struct RoundedSegment RoundedSegment;
+struct RoundedSegment
 {
-U32 vals;
+F32 r;
+V2F32 p1;
+V2F32 p2;
+};
+typedef struct RoundedPolygon RoundedPolygon;
+struct RoundedPolygon
+{
+F32 r;
 U32 count;
+V2F32 *p;
 };
-typedef struct TwinType TwinType;
-struct TwinType
+typedef U32 Shape;
+enum
 {
-U32 val;
+Shape_Circle = 1,
+Shape_Segment = 2,
+Shape_Polygon = 3,
 };
 
-// generated by W:/metadesk/examples/type_metadata/type_metadata.c:910
+// generated by W:/metadesk/examples/type_metadata/type_metadata.c:954
+TypeInfo* type_info_from_shape(Shape v);
+U32 max_slot_from_shape(Shape v);
 
-// generated by W:/metadesk/examples/type_metadata/type_metadata.c:933
+// generated by W:/metadesk/examples/type_metadata/type_metadata.c:977
 extern TypeInfo U32_type_info;
-extern TypeInfo MagicalPoint2D_type_info;
-extern TypeInfo BackwardsArray_type_info;
-extern TypeInfo TwinType_type_info;
-extern TypeInfo TwinType_type_info;
+extern TypeInfo F32_type_info;
+extern TypeInfo V2F32_type_info;
+extern TypeInfo Circle_type_info;
+extern TypeInfo RoundedSegment_type_info;
+extern TypeInfo RoundedPolygon_type_info;
+extern TypeInfo Shape_type_info;
 
 #endif // META_TYPES_H
diff --git a/examples/type_metadata/type_metadata.c b/examples/type_metadata/type_metadata.c
index ae795a3..56c34f6 100644
--- a/examples/type_metadata/type_metadata.c
+++ b/examples/type_metadata/type_metadata.c
@@ -64,8 +64,6 @@ FILE *error_file = 0;
 //  We also use the MD_Map helper to create a string -> pointer mapping so that
 //  we can look up the "processed" info pointers by name after the initial
 //  gather stage.
-//
-// TODO notes on managing output files.
 
 GEN_TypeInfo *first_type = 0;
 GEN_TypeInfo *last_type = 0;
@@ -111,14 +109,6 @@ gen_resolve_type_info_from_referencer(MD_Node *reference)
     return(result);
 }
 
-void
-gen_type_resolve_error(MD_Node *reference)
-{
-    MD_CodeLoc loc = MD_CodeLocFromNode(reference);
-    MD_PrintMessageFmt(error_file, loc, MD_MessageKind_Error,
-                       "could not resolve type name '%.*s'", MD_S8VArg(reference->string));
-}
-
 GEN_TypeEnumerant*
 gen_enumerant_from_name(GEN_TypeInfo *enum_type, MD_String8 name)
 {
@@ -153,6 +143,57 @@ gen_map_case_from_enumerant(GEN_MapInfo *map, GEN_TypeEnumerant *enumerant)
     return(result);
 }
 
+MD_Node*
+gen_get_symbol_md_node_by_name(MD_String8 name)
+{
+    MD_Node *result = MD_NilNode();
+    MD_MapSlot *type_slot = MD_MapLookup(&type_map, MD_MapKeyStr(name));
+    if (type_slot != 0)
+    {
+        GEN_TypeInfo *type_info = (GEN_TypeInfo*)type_slot->val;
+        result = type_info->node;
+    }
+    MD_MapSlot *map_slot = MD_MapLookup(&map_map, MD_MapKeyStr(name));
+    if (map_slot != 0)
+    {
+        GEN_MapInfo *map_info = (GEN_MapInfo*)map_slot->val;
+        result = map_info->node;
+    }
+    return(result);
+}
+
+void
+gen_type_resolve_error(MD_Node *reference)
+{
+    MD_CodeLoc loc = MD_CodeLocFromNode(reference);
+    MD_PrintMessageFmt(error_file, loc, MD_MessageKind_Error,
+                       "could not resolve type name '%.*s'", MD_S8VArg(reference->string));
+}
+
+void
+gen_duplicate_symbol_error(MD_Node *new_node, MD_Node *existing_node)
+{
+    MD_CodeLoc loc = MD_CodeLocFromNode(new_node);
+    MD_PrintMessageFmt(error_file, loc, MD_MessageKind_Error,
+                       "Symbol name '%.*s' is already used",
+                       MD_S8VArg(new_node->string));
+    MD_CodeLoc existing_loc = MD_CodeLocFromNode(existing_node); 
+    MD_PrintMessageFmt(error_file, existing_loc, MD_MessageKind_Note,
+                       "See '%.*s' is already used",
+                       MD_S8VArg(existing_node->string));
+}
+
+void
+gen_check_and_do_duplicate_symbol_error(MD_Node *new_node)
+{
+    MD_Node *existing = gen_get_symbol_md_node_by_name(new_node->string);
+    if (!MD_NodeIsNil(existing))
+    {
+        gen_duplicate_symbol_error(new_node, existing);
+    }
+}
+
+
 //~ analyzers /////////////////////////////////////////////////////////////////
 
 // @notes The first stage of processing is to loop over the top level nodes
@@ -177,7 +218,7 @@ gen_gather_types_and_maps(MD_Node *list)
             
             if (!MD_NodeIsNil(type_tag))
             {
-                // TODO(allen): check for duplicates
+                gen_check_and_do_duplicate_symbol_error(node);
                 
                 GEN_TypeKind kind = GEN_TypeKind_Null;
                 MD_Node   *tag_arg_node = type_tag->first_child;
@@ -215,7 +256,7 @@ gen_gather_types_and_maps(MD_Node *list)
             // gather map
             if (MD_NodeHasTag(node, MD_S8Lit("map"), 0))
             {
-                // TODO(allen): check for duplicates
+                gen_check_and_do_duplicate_symbol_error(node);
                 
                 GEN_MapInfo *map_info = MD_PushArrayZero(arena, GEN_MapInfo, 1);
                 map_info->node = node;
@@ -1189,15 +1230,6 @@ gen_function_definitions_from_maps(FILE *out)
 int
 main(int argc, char **argv)
 {
-#if 1
-    char *argv_dummy[2] = {
-        0,
-        "W:/metadesk/examples/type_metadata/bad_types.mdesk"
-    };
-    argc = 2;
-    argv = argv_dummy;
-#endif
-    
     // setup the global arena
     arena = MD_ArenaAlloc();
     
diff --git a/examples/type_metadata/type_metadata.h b/examples/type_metadata/type_metadata.h
index 5cfbc9c..90f1bf3 100644
--- a/examples/type_metadata/type_metadata.h
+++ b/examples/type_metadata/type_metadata.h
@@ -104,12 +104,18 @@ MD_Node* gen_get_child_value(MD_Node *parent, MD_String8 child_name);
 
 GEN_TypeInfo* gen_resolve_type_info_from_string(MD_String8 name);
 GEN_TypeInfo* gen_resolve_type_info_from_referencer(MD_Node *reference);
-void          gen_type_resolve_error(MD_Node *reference);
 
 GEN_TypeEnumerant* gen_enumerant_from_name(GEN_TypeInfo *enum_type, MD_String8 name);
 
 GEN_MapCase* gen_map_case_from_enumerant(GEN_MapInfo *map, GEN_TypeEnumerant *enumerant);
 
+MD_Node* gen_get_symbol_md_node_by_name(MD_String8 name);
+
+void gen_type_resolve_error(MD_Node *reference);
+void gen_duplicate_symbol_error(MD_Node *new_node, MD_Node *existing_node);
+
+void gen_check_and_do_duplicate_symbol_error(MD_Node *new_node);
+
 //~ analyzers /////////////////////////////////////////////////////////////////
 void gen_gather_types_and_maps(MD_Node *list);
 void gen_check_duplicate_member_names(void);