Clarify comments in enforce_generic_type_consistency().

Some of the pre-existing comments were vague about whether they
referred to all polymorphic types or only the old-style ones.

Also be more consistent about using the "family 1" vs "family 2"
terminology.

Himanshu Upadhyaya and Tom Lane

Discussion: https://postgr.es/m/CAPF61jBUg9XoMPNuLpoZ+h6UZ2VxKdNt3rQL1xw1GOBwjWzAXQ@mail.gmail.com

diff --git a/src/backend/parser/parse_coerce.c b/src/backend/parser/parse_coerce.c
index 1b11cf731ced9f7979807e585cdab55ba12757cf..2ffe47026b9b4427aef520fd652013fbe11cfdd1 100644 (file)
--- a/src/backend/parser/parse_coerce.c
+++ b/src/backend/parser/parse_coerce.c
@@ -2155,8 +2155,8 @@ enforce_generic_type_consistency(const Oid *actual_arg_types,
                        else
                        {
                                /*
-                                * Only way to get here is if all the polymorphic args have
-                                * UNKNOWN inputs
+                                * Only way to get here is if all the family-1 polymorphic
+                                * arguments have UNKNOWN inputs.
                                 */
                                ereport(ERROR,
                                                (errcode(ERRCODE_DATATYPE_MISMATCH),
@@ -2254,10 +2254,10 @@ enforce_generic_type_consistency(const Oid *actual_arg_types,
                        else
                        {
                                /*
-                                * Only way to get here is if all the ANYCOMPATIBLE args have
-                                * UNKNOWN inputs.  Resolve to TEXT as select_common_type()
-                                * would do.  That doesn't license us to use TEXTRANGE,
-                                * though.
+                                * Only way to get here is if all the family-2 polymorphic
+                                * arguments have UNKNOWN inputs.  Resolve to TEXT as
+                                * select_common_type() would do.  That doesn't license us to
+                                * use TEXTRANGE, though.
                                 */
                                anycompatible_typeid = TEXTOID;
                                anycompatible_array_typeid = TEXTARRAYOID;
@@ -2269,7 +2269,7 @@ enforce_generic_type_consistency(const Oid *actual_arg_types,
                        }
                }
 
-               /* replace polymorphic types by selected types */
+               /* replace family-2 polymorphic types by selected types */
                for (int j = 0; j < nargs; j++)
                {
                        Oid                     decl_type = declared_arg_types[j];
@@ -2285,11 +2285,11 @@ enforce_generic_type_consistency(const Oid *actual_arg_types,
        }
 
        /*
-        * If we had any UNKNOWN inputs for polymorphic arguments, re-scan to
-        * assign correct types to them.
+        * If we had any UNKNOWN inputs for family-1 polymorphic arguments,
+        * re-scan to assign correct types to them.
         *
         * Note: we don't have to consider unknown inputs that were matched to
-        * ANYCOMPATIBLE-family arguments, because we forcibly updated their
+        * family-2 polymorphic arguments, because we forcibly updated their
         * declared_arg_types[] positions just above.
         */
        if (have_poly_unknowns)