Fix regression where supertype in field expression would not resolve

A change between 7 and 8 to use exact-matching for document types was
implemented a tad too aggressively, as it should still be possible to
match against supertypes in a document selection field expression.

Let type `B` inherit `A`, and `A` have a field `foo`, and matching a
document of type `B`:

Prior to this fix:
 * `B.foo` _would_ match (implicit supertype field resolving)
 * `A.foo` would _not_ match due to exact type mismatch

After this fix, both will match as generally expected.

1 files changed, 3 insertions, 2 deletions

diff --git a/document/src/tests/documentselectparsertest.cpp b/document/src/tests/documentselectparsertest.cpp
index ce4b69419a3..5e14a080f27 100644
--- a/document/src/tests/documentselectparsertest.cpp
+++ b/document/src/tests/documentselectparsertest.cpp
@@ -673,8 +673,9 @@ TEST_F(DocumentSelectParserTest, operators_1)
     // Inherited doctypes
     PARSE("testdoctype2", *_doc[4], True);
     PARSE("testdoctype2", *_doc[3], False);
-    PARSE("testdoctype1", *_doc[4], False); // testdoctype2 inherits testdoctype1, but we use exact matching for types
-    PARSE("testdoctype1.headerval = 10", *_doc[4], Invalid);
+    PARSE("testdoctype1", *_doc[4], False); // testdoctype2 inherits testdoctype1, but we use exact matching for "standalone" doctype matches.
+    PARSE("testdoctype1.headerval = 10", *_doc[4], True); // But _field lookups_ use is-a type matching semantics.
+    PARSE("testdoctype2.headerval = 10", *_doc[4], True); // Exact type match with parent field also works transparently
 }
 
 TEST_F(DocumentSelectParserTest, operators_2)