From 1fcbbe5f6ceb8bb816811c5f2fb2133a2a32f68f Mon Sep 17 00:00:00 2001 From: Lee Byron Date: Fri, 16 Apr 2021 01:57:34 -0700 Subject: [PATCH] clarify metafields --- spec/Section 3 -- Type System.md | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/spec/Section 3 -- Type System.md b/spec/Section 3 -- Type System.md index 652d83db9..4df0e8fd0 100644 --- a/spec/Section 3 -- Type System.md +++ b/spec/Section 3 -- Type System.md @@ -2088,7 +2088,9 @@ by exactly one possible schema coordinate. A *schema coordinate* may refer to either a defined or built-in *schema element*. For example, `String` and `@deprecated(reason:)` are both valid schema -coordinates which refer to built-in schema elements. +coordinates which refer to built-in schema elements. However it must not refer +to a meta-field. For example, `Business.__typename` is *not* a valid +schema coordinate. Note: A {SchemaCoordinate} is not a definition within a GraphQL {Document}, but a separate standalone grammar, intended to be used by tools to reference types,