Index: src/CompilationState.cc
===================================================================
--- src/CompilationState.cc	(revision 485393c1a199e5cf69f7268525ccb95724f402ff)
+++ src/CompilationState.cc	(revision 372b6d34a37306819c474eb057a4c06dca076d4d)
@@ -9,7 +9,7 @@
 // Author           : Rob Schluntz
 // Created On       : Mon Ju1 30 10:47:01 2018
-// Last Modified By : Henry Xue
-// Last Modified On : Tue Jul 20 04:27:35 2021
-// Update Count     : 5
+// Last Modified By : Peter A. Buhr
+// Last Modified On : Mon Apr 10 19:12:50 2023
+// Update Count     : 6
 //
 
@@ -27,4 +27,5 @@
 	expraltp = false,
 	genericsp = false,
+	invariant = false,
 	libcfap = false,
 	nopreludep = false,
Index: src/CompilationState.h
===================================================================
--- src/CompilationState.h	(revision 485393c1a199e5cf69f7268525ccb95724f402ff)
+++ src/CompilationState.h	(revision 372b6d34a37306819c474eb057a4c06dca076d4d)
@@ -9,7 +9,7 @@
 // Author           : Rob Schluntz
 // Created On       : Mon Ju1 30 10:47:01 2018
-// Last Modified By : Henry Xue
-// Last Modified On : Tue Jul 20 04:27:35 2021
-// Update Count     : 5
+// Last Modified By : Peter A. Buhr
+// Last Modified On : Mon Apr 10 19:12:53 2023
+// Update Count     : 6
 //
 
@@ -26,4 +26,5 @@
 	expraltp,
 	genericsp,
+	invariant,
 	libcfap,
 	nopreludep,
Index: src/main.cc
===================================================================
--- src/main.cc	(revision 485393c1a199e5cf69f7268525ccb95724f402ff)
+++ src/main.cc	(revision 372b6d34a37306819c474eb057a4c06dca076d4d)
@@ -9,7 +9,7 @@
 // Author           : Peter Buhr and Rob Schluntz
 // Created On       : Fri May 15 23:12:02 2015
-// Last Modified By : Andrew Beach
-// Last Modified On : Thr Feb 16 10:08:00 2023
-// Update Count     : 680
+// Last Modified By : Peter A. Buhr
+// Last Modified On : Mon Apr 10 21:12:17 2023
+// Update Count     : 682
 //
 
@@ -504,5 +504,5 @@
 
 
-static const char optstring[] = ":c:ghlLmNnpdP:S:twW:D:";
+static const char optstring[] = ":c:ghilLmNnpdP:S:twW:D:";
 
 enum { PreludeDir = 128 };
@@ -511,7 +511,8 @@
 	{ "gdb", no_argument, nullptr, 'g' },
 	{ "help", no_argument, nullptr, 'h' },
+	{ "invariant", no_argument, nullptr, 'i' },
 	{ "libcfa", no_argument, nullptr, 'l' },
 	{ "linemarks", no_argument, nullptr, 'L' },
-	{ "no-main", no_argument, 0, 'm' },
+	{ "no-main", no_argument, nullptr, 'm' },
 	{ "no-linemarks", no_argument, nullptr, 'N' },
 	{ "no-prelude", no_argument, nullptr, 'n' },
@@ -532,4 +533,5 @@
 	"wait for gdb to attach",							// -g
 	"print translator help message",					// -h
+	"invariant checking during AST passes",				// -i
 	"generate libcfa.c",								// -l
 	"generate line marks",								// -L
@@ -625,4 +627,7 @@
 			usage( argv );								// no return
 			break;
+		  case 'i':										// invariant checking
+			invariant = true;
+			break;
 		  case 'l':										// generate libcfa.c
 			libcfap = true;