Cast result of copyObject() to correct type

copyObject() is declared to return void *, which allows easily assigning
the result independent of the input, but it loses all type checking.

If the compiler supports typeof or something similar, cast the result to
the input type.  This creates a greater amount of type safety.  In some
cases, where the result is assigned to a generic type such as Node * or
Expr *, new casts are now necessary, but in general casts are now
unnecessary in the normal case and indicate that something unusual is
happening.

Reviewed-by: Mark Dilger <hornschnorter@gmail.com>

1 files changed, 40 insertions, 0 deletions

diff --git a/configure b/configure
index 4b8229e959f..3c92cabb924 100755
--- a/configure
+++ b/configure
@@ -11668,6 +11668,46 @@ if test x"$pgac_cv__static_assert" = xyes ; then
 $as_echo "#define HAVE__STATIC_ASSERT 1" >>confdefs.h
 
 fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for typeof" >&5
+$as_echo_n "checking for typeof... " >&6; }
+if ${pgac_cv_c_typeof+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  pgac_cv_c_typeof=no
+for pgac_kw in typeof __typeof__ decltype; do
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main ()
+{
+int x = 0;
+$pgac_kw(x) y;
+y = x;
+return y;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"; then :
+  pgac_cv_c_typeof=$pgac_kw
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
+  test "$pgac_cv_c_typeof" != no && break
+done
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $pgac_cv_c_typeof" >&5
+$as_echo "$pgac_cv_c_typeof" >&6; }
+if test "$pgac_cv_c_typeof" != no; then
+
+$as_echo "#define HAVE_TYPEOF 1" >>confdefs.h
+
+  if test "$pgac_cv_c_typeof" != typeof; then
+
+$as_echo "#define typeof \$pgac_cv_c_typeof" >>confdefs.h
+
+  fi
+fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for __builtin_types_compatible_p" >&5
 $as_echo_n "checking for __builtin_types_compatible_p... " >&6; }
 if ${pgac_cv__types_compatible+:} false; then :