diff --git a/src/cmd/ksh93/sh/parse.c b/src/cmd/ksh93/sh/parse.c
index 86fdb3e23..f1474331e 100644
--- a/src/cmd/ksh93/sh/parse.c
+++ b/src/cmd/ksh93/sh/parse.c
@@ -234,7 +234,14 @@ static void check_typedef(struct comnod *tp, char intypeset)
 		}
 	}
 	if(cp)
+	{
+		if(!dcl_tree)
+		{
+			dcl_tree = dtopen(&_Nvdisc, Dtoset);
+			dtview(sh.bltin_tree, dcl_tree);
+		}
 		nv_onattr(sh_addbuiltin(cp, (Shbltin_f)SYSTRUE->nvalue.bfp, NIL(void*)), NV_BLTIN|BLT_DCL);
+	}
 }
 /*
  * (De)activate an internal declaration built-ins tree into which check_typedef() can pre-add dummy type
@@ -250,9 +257,8 @@ static void dcl_hacktivate(void)
 {
 	if(dcl_recursion++)
 		return;
-	if(!dcl_tree)
-		dcl_tree = dtopen(&_Nvdisc, Dtoset);
-	dtview(sh.bltin_tree, dcl_tree);
+	if(dcl_tree)
+		dtview(sh.bltin_tree, dcl_tree);
 	orig_exit = error_info.exit;
 	error_info.exit = dcl_exit;
 }
@@ -261,7 +267,12 @@ static void dcl_dehacktivate(void)
 	if(!dcl_recursion || --dcl_recursion)
 		return;
 	error_info.exit = orig_exit;
-	dtview(sh.bltin_tree, NIL(Dt_t*));
+	if(dcl_tree)
+	{
+		dtview(sh.bltin_tree, NIL(Dt_t*));
+		if(!sh.shcomp)
+			dtclear(dcl_tree);
+	}
 }
 static noreturn void dcl_exit(int e)
 {
diff --git a/src/cmd/ksh93/tests/types.sh b/src/cmd/ksh93/tests/types.sh
index abfd1c7da..4b9bb36fa 100755
--- a/src/cmd/ksh93/tests/types.sh
+++ b/src/cmd/ksh93/tests/types.sh
@@ -658,6 +658,8 @@ if	false
 then	typeset -T PARSER_t=(typeset name=foobar)
 fi
 PATH=/dev/null command -v PARSER_t >/dev/null && err_exit "PARSER_t incompletely defined though definition was never executed"
+(PATH=/dev/null eval 'PARSER_t x=(name=y)') 2>/dev/null
+(($?==3)) || err_exit "PARSER_t assignment not a syntax error though definition was never executed"
 
 unset v
 got=$( set +x; redirect 2>&1; typeset -T Subsh_t=(typeset -i x); Subsh_t -a v=( (x=1) (x=2) (x=3) ); typeset -p v )
@@ -675,7 +677,7 @@ exp=': trap: is a special shell builtin'
 
 # ======
 # Bugs involving scripts without a #! path
-# Hashbangless scripts are execeuted in a reinitialised fork of ksh, which is very bug-prone.
+# Hashbangless scripts are executed in a reinitialised fork of ksh, which is very bug-prone.
 # https://github.com/ksh93/ksh/issues/350
 # Some of these fixed bugs don't involve types at all, but the tests need to go somewhere.
 # Plus, invoking these from an environment with a bunch of types defined is an additional test.