diff --git a/pod/perldiag.pod b/pod/perldiag.pod
index b05554939e..6f55f15417 100644
--- a/pod/perldiag.pod
+++ b/pod/perldiag.pod
@@ -4741,6 +4741,14 @@ regardless of what name the caller used.
 (W overload) The call to overload::constant contained an odd number of
 arguments.  The arguments should come in pairs.
 
+=item Odd number of arguments passed to "%s" constructor
+
+(S) The constructor for the given class was called with an odd
+number of arguments.
+
+Class constructors accept named arguments as a list and expect pairs
+of name followed by value as if you were initialising a hash.
+
 =item Odd number of elements in anonymous hash
 
 (W misc) You specified an odd number of elements to initialize a hash,
@@ -7320,6 +7328,11 @@ whereabouts in the regular expression the escape was discovered.
 (F) You attempted to add a named attribute to a C<field> definition, but
 perl does not recognise the name of the requested attribute.
 
+=item Unrecognised parameters for "%s" constructor: %s
+
+(F) You called new on a class but supplied a parameter name that
+didn't match a class field name.
+
 =item Unrecognized signal name "%s"
 
 (F) You specified a signal name to the kill() function that was not
diff --git a/t/porting/diag.t b/t/porting/diag.t
index 4f47bb690f..dbc86470ff 100644
--- a/t/porting/diag.t
+++ b/t/porting/diag.t
@@ -243,6 +243,7 @@ my $specialformats_re = qr/%$format_modifiers"\s*($specialformats)(\s*(?:"|\z))?
 # We skip the bodies of most XS functions, but not within these files
 my @include_xs_files = (
   "builtin.c",
+  "class.c",
   "universal.c",
 );