diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index 2f707ce..01728ed 100644
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,5 +1,10 @@
 2018-12-10  Steven G. Kargl  <kargl@gcc.gnu.org>
 
+	PR fortran/87922
+	* io.c (gfc_match_open): Additional checks on ASYNCHRONOUS.
+
+2018-12-10  Steven G. Kargl  <kargl@gcc.gnu.org>
+
 	PR fortran/88269
 	* io.c (io_constraint): Update macro. If locus line buffer is NULL,
 	use gfc_current_locus in error messages.
diff --git a/gcc/fortran/io.c b/gcc/fortran/io.c
index 8d54107..8415df1 100644
--- a/gcc/fortran/io.c
+++ b/gcc/fortran/io.c
@@ -2205,6 +2205,21 @@
       if (!is_char_type ("ASYNCHRONOUS", open->asynchronous))
 	goto cleanup;
 
+      if (open->asynchronous->ts.kind != 1)
+	{
+	  gfc_error ("ASYNCHRONOUS= specifier at %L must be of default "
+		     "CHARACTER kind", &open->asynchronous->where);
+	  return MATCH_ERROR;
+	}
+
+      if (open->asynchronous->expr_type == EXPR_ARRAY
+	  || open->asynchronous->expr_type == EXPR_STRUCTURE)
+	{
+	  gfc_error ("ASYNCHRONOUS= specifier at %L must be scalar",
+		     &open->asynchronous->where);
+	  return MATCH_ERROR;
+	}
+
       if (open->asynchronous->expr_type == EXPR_CONSTANT)
 	{
 	  static const char * asynchronous[] = { "YES", "NO", NULL };
@@ -3799,6 +3814,21 @@
       if (!is_char_type ("ASYNCHRONOUS", dt->asynchronous))
 	return MATCH_ERROR;
 
+      if (dt->asynchronous->ts.kind != 1)
+	{
+	  gfc_error ("ASYNCHRONOUS= specifier at %L must be of default "
+		     "CHARACTER kind", &dt->asynchronous->where);
+	  return MATCH_ERROR;
+	}
+
+      if (dt->asynchronous->expr_type == EXPR_ARRAY
+	  || dt->asynchronous->expr_type == EXPR_STRUCTURE)
+	{
+	  gfc_error ("ASYNCHRONOUS= specifier at %L must be scalar",
+		     &dt->asynchronous->where);
+	  return MATCH_ERROR;
+	}
+
       if (!compare_to_allowed_values
 		("ASYNCHRONOUS", asynchronous, NULL, NULL,
 		 dt->asynchronous->value.character.string,
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 5cbaa82..e4c9d4a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,11 @@
 2018-12-10  Steven G. Kargl  <kargl@gcc.gnu.org>
 
+	PR fortran/97922
+	* gfortran.dg/io_constraints_8.f90: Update error message.
+	* gfortran.dg/pr87922.f90: New test.
+
+2018-12-10  Steven G. Kargl  <kargl@gcc.gnu.org>
+
 	PR fortran/88269
 	* gfortran.dg/pr88269.f90: New test.
 
diff --git a/gcc/testsuite/gfortran.dg/io_constraints_8.f90 b/gcc/testsuite/gfortran.dg/io_constraints_8.f90
index 81cece4..216a41b 100644
--- a/gcc/testsuite/gfortran.dg/io_constraints_8.f90
+++ b/gcc/testsuite/gfortran.dg/io_constraints_8.f90
@@ -14,7 +14,7 @@
 
 OPEN(99, access=4_'direct')     ! { dg-error "must be a character string of default kind" }
 OPEN(99, action=4_'read')       ! { dg-error "must be a character string of default kind" }
-OPEN(99, asynchronous=4_'no')   ! { dg-error "must be a character string of default kind" })
+OPEN(99, asynchronous=4_'no')   ! { dg-error "must be of default CHARACTER kind" }
 OPEN(99, blank=4_'null')        ! { dg-error "must be a character string of default kind" }
 OPEN(99, decimal=4_'comma')     ! { dg-error "must be a character string of default kind" }
 OPEN(99, delim=4_'quote')       ! { dg-error "must be a character string of default kind" }
diff --git a/gcc/testsuite/gfortran.dg/pr87922.f90 b/gcc/testsuite/gfortran.dg/pr87922.f90
new file mode 100644
index 0000000..8bdc6bc
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr87922.f90
@@ -0,0 +1,10 @@
+! { dg-do compile }
+! PR fortran/87922
+subroutine p
+   read(1, asynchronous=['no'])           ! { dg-error "must be scalar" }
+   read(1, asynchronous=[character::])    ! { dg-error "must be scalar" }
+end
+subroutine q
+   write(1, asynchronous=['no'])          ! { dg-error "must be scalar" }
+   write(1, asynchronous=[character::])   ! { dg-error "must be scalar" }
+end