Index: libcfa/src/containers/list.hfa
===================================================================
--- libcfa/src/containers/list.hfa	(revision 3f7d0b4048753fae94a809adde76e0bc43c4b45d)
+++ libcfa/src/containers/list.hfa	(revision 4d741e9c9f39fd8ef3618df94fdff5f3077f862b)
@@ -71,10 +71,10 @@
 		// will collapse to single pointer with tag bit
 	};
-	inline void ?{}( $mgd_link(tE) &this, tE* elem ) {
+	static inline void ?{}( $mgd_link(tE) &this, tE* elem ) {
 		(this.elem){ elem };
 		(this.terminator){ 0p };
 		(this.is_terminator){ 0 };
 	}
-	inline void ?{}( $mgd_link(tE) &this, void * terminator ) {
+	static inline void ?{}( $mgd_link(tE) &this, void * terminator ) {
 		(this.elem){ 0p };
 		(this.terminator){ terminator };
@@ -82,5 +82,5 @@
 	}
 	forall ( otype tInit | { void ?{}( $mgd_link(tE) &, tInit); } )
-	void ?=?( $mgd_link(tE) &this, tInit i ) {
+	static inline void ?=?( $mgd_link(tE) &this, tInit i ) {
 		^?{}( this );
 		?{}( this, i );
@@ -93,5 +93,5 @@
 		$mgd_link(tE) prev;
 	};
-	inline void ?{}( $dlinks(tE) &this ) {
+	static inline void ?{}( $dlinks(tE) &this ) {
 		(this.next){ (tE *)0p };
 		(this.prev){ (tE *)0p };
@@ -132,16 +132,46 @@
 	// an empty dlist
 	// links refer to self, making a tight circle
-	void ?{}( dlist(Tnode, Telem) & this ) {
+	static inline void ?{}( dlist(Tnode, Telem) & this ) {
 		$mgd_link(Telem) selfRef = (void *) &this;
 		( this.$links ) { selfRef, selfRef };
 	}
 
-	Telem & ?`first( dlist(Tnode, Telem) &l ) {
+	static inline Telem & ?`first( dlist(Tnode, Telem) &l ) {
 		return * l.$links.next.elem;
 	}
 
-	Telem & ?`last( dlist(Tnode, Telem) &l ) {
+	static inline Telem & ?`last( dlist(Tnode, Telem) &l ) {
 		return * l.$links.prev.elem;
 	}
+
+	#if !defined(NDEBUG) && (defined(__CFA_DEBUG__) || defined(__CFA_VERIFY__))
+	static bool $validate_fwd( dlist(Tnode, Telem) & this ) {
+		Tnode * it = & $tempcv_e2n( this`first );
+		if (!it) return (& this`last == 0p);
+
+		while( $next_link(*it).elem ) {
+			it = & $tempcv_e2n( * $next_link(*it).elem );
+		}
+
+		return ( it == & $tempcv_e2n( this`last ) ) &&
+			   ( $next_link(*it).is_terminator ) &&
+			   ( ((dlist(Tnode, Telem)*)$next_link(*it).terminator) == &this );
+	}
+	static bool $validate_rev( dlist(Tnode, Telem) & this ) {
+		Tnode * it = & $tempcv_e2n( this`last );
+		if (!it) return (& this`first == 0p);
+
+		while( $prev_link(*it).elem ) {
+			it = & $tempcv_e2n( * $prev_link(*it).elem );
+		}
+
+		return ( it == & $tempcv_e2n( this`first ) ) &&
+			   ( $prev_link(*it).is_terminator ) &&
+			   ( ((dlist(Tnode, Telem)*)$prev_link(*it).terminator) == &this );
+	}
+	static bool validate( dlist(Tnode, Telem) & this ) {
+		return $validate_fwd(this) && $validate_rev(this);
+	}
+	#endif
 
 	static inline void insert_after(Tnode &list_pos, Telem &to_insert) {
@@ -152,5 +182,5 @@
 		assert($next_link(singleton_to_insert).elem == 0p);
 		$prev_link(singleton_to_insert) = & $tempcv_n2e(list_pos);
-		$next_link(singleton_to_insert) = $next_link(list_pos).elem;
+		$next_link(singleton_to_insert) = $next_link(list_pos);
 		if ($next_link(list_pos).is_terminator) {
 			dlist(Tnode, Telem) *list = $next_link(list_pos).terminator;
@@ -175,5 +205,5 @@
 		assert($next_link(singleton_to_insert).elem == 0p);
 		$next_link(singleton_to_insert) = & $tempcv_n2e(list_pos);
-		$prev_link(singleton_to_insert) = $prev_link(list_pos).elem;
+		$prev_link(singleton_to_insert) = $prev_link(list_pos);
 		if ($prev_link(list_pos).is_terminator) {
 			dlist(Tnode, Telem) *list = $prev_link(list_pos).terminator;
Index: tests/list/dlist-insert-remove.cfa
===================================================================
--- tests/list/dlist-insert-remove.cfa	(revision 3f7d0b4048753fae94a809adde76e0bc43c4b45d)
+++ tests/list/dlist-insert-remove.cfa	(revision 4d741e9c9f39fd8ef3618df94fdff5f3077f862b)
@@ -258,4 +258,6 @@
 	dlist(fred_in_mine, fred) lf;
 
+	verify(validate(lf));
+
 	printMyFreddies(f1, f2, 1);     // 3.14; 3.14; 0.5; 0.5
 	printYourFreddies(f1, f2, 1);   // 3.14; 3.14; 0.5; 0.5
@@ -264,4 +266,6 @@
 	insert_first(lf, f1);
 
+	verify(validate(lf));
+
 	printMyFreddies(f1, f2, 0);     // 3.14, 0.5; 3.14; 0.5; 0.5, 3.14 (modified)
 	printYourFreddies(f1, f2, 0);   // 3.14; 3.14; 0.5; 0.5 (unmodified)
@@ -275,4 +279,6 @@
 	dlist(fred_in_yours, fred) lf;
 
+	verify(validate(lf));
+
 	printMyFreddies(f1, f2, 1);     // 3.14; 3.14; 0.5; 0.5
 	printYourFreddies(f1, f2, 1);   // 3.14; 3.14; 0.5; 0.5
@@ -281,4 +287,6 @@
 	insert_first(lf, f1);
 
+	verify(validate(lf));
+
 	printMyFreddies(f1, f2, 0);     // 3.14; 3.14; 0.5; 0.5 (unmodified)
 	printYourFreddies(f1, f2, 0);   // 3.14, 0.5; 3.14; 0.5; 0.5, 3.14 (modified)
@@ -292,4 +300,5 @@
 	dlist(mary, mary) lm;
 
+	verify(validate(lm));
 	printMariatheotokos(m1, m2, 1); // 3.14; 3.14; 0.5; 0.5
 
@@ -298,4 +307,5 @@
 
 	printMariatheotokos(m1, m2, 0); // 3.14, 0.5; 3.14; 0.5; 0.5, 3.14 (modified)
+	verify(validate(lm));
 }
 
@@ -317,4 +327,6 @@
 	dlist(fred_in_mine, fred) lf;
 
+	verify(validate(lf));
+
 	printMyFreddies(f1, f2, 1);     // 3.14; 3.14; 0.5; 0.5
 	printYourFreddies(f1, f2, 1);   // 3.14; 3.14; 0.5; 0.5
@@ -323,4 +335,6 @@
 	insert_last(lf, f2);
 
+	verify(validate(lf));
+
 	printMyFreddies(f1, f2, 0);     // 3.14, 0.5; 3.14; 0.5; 0.5, 3.14 (modified)
 	printYourFreddies(f1, f2, 0);   // 3.14; 3.14; 0.5; 0.5 (unmodified)
@@ -334,4 +348,6 @@
 	dlist(fred_in_yours, fred) lf;
 
+	verify(validate(lf));
+
 	printMyFreddies(f1, f2, 1);     // 3.14; 3.14; 0.5; 0.5
 	printYourFreddies(f1, f2, 1);   // 3.14; 3.14; 0.5; 0.5
@@ -340,4 +356,6 @@
 	insert_last(lf, f2);
 
+	verify(validate(lf));
+
 	printMyFreddies(f1, f2, 0);     // 3.14; 3.14; 0.5; 0.5 (unmodified)
 	printYourFreddies(f1, f2, 0);   // 3.14, 0.5; 3.14; 0.5; 0.5, 3.14 (modified)
@@ -351,4 +369,5 @@
 	dlist(mary, mary) lm;
 
+	verify(validate(lm));
 	printMariatheotokos(m1, m2, 1); // 3.14; 3.14; 0.5; 0.5
 
@@ -356,4 +375,5 @@
 	insert_last(lm, m2);
 
+	verify(validate(lm));
 	printMariatheotokos(m1, m2, 0); // 3.14, 0.5; 3.14; 0.5; 0.5, 3.14 (modified)
 }
@@ -384,5 +404,9 @@
 	assert(& lf`last == & f1);
 
+	verify(validate(lf));
+
 	insert_after(f1`in_mine, f2);
+
+	verify(validate(lf));
 
 	printMyFreddies(f1, f2, 0);     // 3.14, 0.5; 3.14; 0.5; 0.5, 3.14 (modified)
@@ -408,5 +432,9 @@
 	assert(& lf`last == & f1);
 
+	verify(validate(lf));
+
 	insert_after(f1`in_yours, f2);
+
+	verify(validate(lf));
 
 	printMyFreddies(f1, f2, 0);     // 3.14; 3.14; 0.5; 0.5 (unmodified)
@@ -432,5 +460,9 @@
 	assert(& lm`last == & m1);
 
+	verify(validate(lm));
+
 	insert_after(m1, m2);
+
+	verify(validate(lm));
 
 	printMariatheotokos(m1, m2, 0); // 3.14, 0.5; 3.14; 0.5; 0.5, 3.14 (modified)
@@ -465,5 +497,9 @@
 	assert(& lf`last == & f2);
 
+	verify(validate(lf));
+
 	insert_before(f2`in_mine, f1);
+
+	verify(validate(lf));
 
 	printMyFreddies(f1, f2, 0);     // 3.14, 0.5; 3.14; 0.5; 0.5, 3.14 (modified)
@@ -489,5 +525,9 @@
 	assert(& lf`last == & f2);
 
+	verify(validate(lf));
+
 	insert_before(f2`in_yours, f1);
+
+	verify(validate(lf));
 
 	printMyFreddies(f1, f2, 0);     // 3.14; 3.14; 0.5; 0.5 (unmodified)
@@ -513,5 +553,9 @@
 	assert(& lm`last == & m2);
 
+	verify(validate(lm));
+
 	insert_before(m2, m1);
+
+	verify(validate(lm));
 
 	printMariatheotokos(m1, m2, 0); // 3.14, 0.5; 3.14; 0.5; 0.5, 3.14 (modified)
@@ -822,5 +866,11 @@
 	printYourFreddies(fly`first, fly`last, 1);   // 1.7, 2.7, 3.7;  1.7;  3.7;  3.7, 2.7, 1.7 
 
+	verify(validate(fly));
+	verify(validate(flm));
+
 	remove(f1`in_mine);
+
+	verify(validate(fly));
+	verify(validate(flm));
 
 	printMyFreddies(flm`first, flm`last, 0);     // 2.7, 3.7;       2.7;  3.7;  3.7, 2.7      (modified)
@@ -854,5 +904,11 @@
 	printYourFreddies(fly`first, fly`last, 1);   // 1.7, 2.7, 3.7;  1.7;  3.7;  3.7, 2.7, 1.7 
 
+	verify(validate(fly));
+	verify(validate(flm));
+
 	remove(f1`in_yours);
+
+	verify(validate(fly));
+	verify(validate(flm));
 
 	printMyFreddies(flm`first, flm`last, 0);     // 1.7, 2.7, 3.7;  1.7;  3.7;  3.7, 2.7, 1.7 (unmodified)
@@ -880,5 +936,9 @@
 	printMariatheotokos(ml`first, ml`last, 1);     // 1.7, 2.7, 3.7;  1.7;  3.7;  3.7, 2.7, 1.7 
 
+	verify(validate(ml));
+
 	remove(m1);
+
+	verify(validate(ml));
 
 	printMariatheotokos(ml`first, ml`last, 0);     // 2.7, 3.7;       2.7;  3.7;  3.7, 2.7      (modified)
@@ -921,5 +981,11 @@
 	printYourFreddies(fly`first, fly`last, 1);   // 1.7, 2.7, 3.7;  1.7;  3.7;  3.7, 2.7, 1.7 
 
+	verify(validate(fly));
+	verify(validate(flm));
+
 	remove(f3`in_mine);
+
+	verify(validate(fly));
+	verify(validate(flm));
 
 	printMyFreddies(flm`first, flm`last, 0);     // 1.7, 2.7;       1.7;  2.7;  2.7, 1.7      (modified)
@@ -953,5 +1019,11 @@
 	printYourFreddies(fly`first, fly`last, 1);   // 1.7, 2.7, 3.7;  1.7;  3.7;  3.7, 2.7, 1.7 
 
+	verify(validate(fly));
+	verify(validate(flm));
+
 	remove(f3`in_yours);
+
+	verify(validate(fly));
+	verify(validate(flm));
 
 	printMyFreddies(flm`first, flm`last, 0);     // 1.7, 2.7, 3.7;  1.7;  3.7;  3.7, 2.7, 1.7 (unmodified)
@@ -979,5 +1051,9 @@
 	printMariatheotokos(ml`first, ml`last, 1);     // 1.7, 2.7, 3.7;  1.7;  3.7;  3.7, 2.7, 1.7 
 
+	verify(validate(ml));
+
 	remove(m3);
+
+	verify(validate(ml));
 
 	printMariatheotokos(ml`first, ml`last, 0);     // 1.7, 2.7;       1.7;  2.7;  2.7, 1.7      (modified)
@@ -1014,5 +1090,11 @@
 	printYourFreddies(fly`first, fly`last, 1);   // 0.7; 0.7; 0.7; 0.7
 
+	verify(validate(fly));
+	verify(validate(flm));
+
 	remove(f`in_mine);
+
+	verify(validate(fly));
+	verify(validate(flm));
 
 	assert(& flm`first == 0p);
@@ -1029,4 +1111,6 @@
 
 	insert_last(flm, f);
+	verify(validate(fly));
+	verify(validate(flm));
 	printMyFreddies(flm`first, flm`last, 0);     // 0.7; 0.7; 0.7; 0.7
 }
@@ -1045,5 +1129,11 @@
 	printYourFreddies(fly`first, fly`last, 1);   // 0.7; 0.7; 0.7; 0.7
 
+	verify(validate(fly));
+	verify(validate(flm));
+
 	remove(f`in_yours);
+
+	verify(validate(fly));
+	verify(validate(flm));
 
 	assert(& fly`first == 0p);
@@ -1060,4 +1150,6 @@
 
 	insert_last(fly, f);
+	verify(validate(fly));
+	verify(validate(flm));
 	printYourFreddies(fly`first, fly`last, 0);     // 0.7; 0.7; 0.7; 0.7
 }
@@ -1072,5 +1164,9 @@
 	printMariatheotokos(ml`first, ml`last, 1);     // 0.7; 0.7; 0.7; 0.7
 
+	verify(validate(ml));
+
 	remove(m);
+
+	verify(validate(ml));
 
 	assert(& ml`first == 0p);
@@ -1085,4 +1181,5 @@
 
 	insert_last(ml, m);
+	verify(validate(ml));
 	printMariatheotokos(ml`first, ml`last, 0);     // 0.7; 0.7; 0.7; 0.7
 }