diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index 3f4ab3c9fa4712a5bdb275d9bf2e255b11015a2d..c32304bf9529362d76d4f462adbd0a9977e4ba49 100644
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,3 +1,9 @@
+2007-03-22  Tobias Schlüter  <tobi@gcc.gnu.org>
+
+	PR fortran/20897
+	* decl.c (gfc_match_derived_decl): Reliably reject
+	'doubleprecision' and 'doublecomplex' as type names.
+
 2007-03-19  Francois-Xavier Coudert  <coudert@clipper.ens.fr>
 
 	PR fortran/31203
diff --git a/gcc/fortran/decl.c b/gcc/fortran/decl.c
index 09ded01d27c3808ffc072fd5bf3fcb4dfdb23367..570a036c0419b88c39d7483ef924c02f2f9e4742 100644
--- a/gcc/fortran/decl.c
+++ b/gcc/fortran/decl.c
@@ -4341,12 +4341,16 @@ loop:
     return m;
 
   /* Make sure the name isn't the name of an intrinsic type.  The
-     'double precision' type doesn't get past the name matcher.  */
+     'double {precision,complex}' types don't get past the name
+     matcher, unless they're written as a single word or in fixed
+     form.  */
   if (strcmp (name, "integer") == 0
       || strcmp (name, "real") == 0
       || strcmp (name, "character") == 0
       || strcmp (name, "logical") == 0
-      || strcmp (name, "complex") == 0)
+      || strcmp (name, "complex") == 0
+      || strcmp (name, "doubleprecision") == 0
+      || strcmp (name, "doublecomplex") == 0)
     {
       gfc_error ("Type name '%s' at %C cannot be the same as an intrinsic "
 		 "type", name);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 656d05bd5ec45bcaeaa26ef93f9243db816df91d..d993a15c1f6ae93bff1ea626026349eec8f72bc7 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2007-03-22  Tobias Schlüter  <tobi@gcc.gnu.org>
+
+	PR fortran/20897
+	* gfortran.dg/derived_name_1.f90: New.
+	* gfortran.dg/derived_name_2.f: New.
+
 2007-03-21  Richard Sandiford  <richard@codesourcery.com>
 
 	* lib/target-supports.exp (check_effective_target_nonpic): New
diff --git a/gcc/testsuite/gfortran.dg/derived_name_1.f90 b/gcc/testsuite/gfortran.dg/derived_name_1.f90
new file mode 100644
index 0000000000000000000000000000000000000000..9c6b1775d11d72e0f252d6c9144528640935e20b
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/derived_name_1.f90
@@ -0,0 +1,19 @@
+! { dg-do compile }
+! PR 20897
+! Make sure intrinsic type names do not appear as names of derived types
+type integer ! { dg-error "cannot be the same as an intrinsic type" }
+type real    ! { dg-error "cannot be the same as an intrinsic type" }
+type complex ! { dg-error "cannot be the same as an intrinsic type" }
+type character ! { dg-error "cannot be the same as an intrinsic type" }
+type logical ! { dg-error "cannot be the same as an intrinsic type" }
+type complex ! { dg-error "cannot be the same as an intrinsic type" }
+type double precision ! { dg-error "Unclassifiable statement" }
+type doubleprecision ! { dg-error "cannot be the same as an intrinsic type" }
+type double complex ! { dg-error "Unclassifiable statement" }
+type doublecomplex ! { dg-error "cannot be the same as an intrinsic type" }
+
+type x
+   integer y
+end type x
+end
+
diff --git a/gcc/testsuite/gfortran.dg/derived_name_2.f b/gcc/testsuite/gfortran.dg/derived_name_2.f
new file mode 100644
index 0000000000000000000000000000000000000000..a89dcdfbd71bcda9129a5f111414e6eb70fcbbc2
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/derived_name_2.f
@@ -0,0 +1,19 @@
+! { dg-do compile }
+! PR 20897
+! Make sure intrinsic type names do not appear as names of derived types
+      type integer     ! { dg-error "cannot be the same as an intrinsic type" }
+      type real        ! { dg-error "cannot be the same as an intrinsic type" }
+      type complex     ! { dg-error "cannot be the same as an intrinsic type" }
+      type character   ! { dg-error "cannot be the same as an intrinsic type" }
+      type logical     ! { dg-error "cannot be the same as an intrinsic type" }
+      type complex     ! { dg-error "cannot be the same as an intrinsic type" }
+      type double precision     ! { dg-error "cannot be the same as an intrinsic type" }
+      type doubleprecision      ! { dg-error "cannot be the same as an intrinsic type" }
+      type double complex       ! { dg-error "cannot be the same as an intrinsic type" }
+      type doublecomplex        ! { dg-error "cannot be the same as an intrinsic type" }
+
+      type x
+      integer y
+      end type x
+      end
+