complete M7 type metadata

fec/src/types.h

@@ -4,9 +4,10 @@
 #include "ast.h"
 
 typedef enum FeTypeKind {
-    FE_TYPE_ERROR, FE_TYPE_ERROR_UNION, FE_TYPE_VOID, FE_TYPE_BOOL, FE_TYPE_CHAR, FE_TYPE_INT,
+    FE_TYPE_ERROR, FE_TYPE_ERROR_UNION, FE_TYPE_OPTIONAL,
+    FE_TYPE_VOID, FE_TYPE_BOOL, FE_TYPE_CHAR, FE_TYPE_INT,
     FE_TYPE_STRUCT, FE_TYPE_ENUM, FE_TYPE_ARRAY, FE_TYPE_SLICE, FE_TYPE_STR,
-    FE_TYPE_REF, FE_TYPE_OWNED, FE_TYPE_OPTIONAL, FE_TYPE_UNKNOWN
+    FE_TYPE_REF, FE_TYPE_OWNED, FE_TYPE_UNKNOWN
 } FeTypeKind;
 
 typedef struct FeFieldType FeFieldType;
@@ -33,6 +34,8 @@ struct FeType {
     char name[64];
     char *cname;
     char *maker;
+    char *none_cname;
+    char *unwrap_cname;
     char *indexer;
     char *slicer;
     char *full_slicer;
@@ -48,10 +51,10 @@ struct FeType {
     unsigned long length;
     unsigned long size;
     unsigned align;
+    /* Element/payload type for refs, owners, slices and optionals.  For an
+       error union this is the nominal error identity; NULL means core.Error. */
     FeType *elem;
-    /* Success value for an error union; !void is represented directly.
-       For a nominal E!T created by M7, elem holds E.  A null elem denotes
-       the built-in core.Error shorthand !T. */
+    /* Success value for an error union. */
     FeType *error_value;
     int ref_mut;
     FeFieldType *fields;