fixes

usethesource · Nov 3, 2023 · 268e9c0 · 268e9c0
1 parent 37a36c6
commit 268e9c0
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diff --git a/src/org/rascalmpl/library/lang/rascal/matching/Fingerprint.rsc b/src/org/rascalmpl/library/lang/rascal/matching/Fingerprint.rsc
@@ -58,6 +58,7 @@ implement a sensible encoding that follows the contract and tries to differentia
 int concreteFingerprint(appl(Production p, list[Tree] _))                   = concreteFingerprint(p);
 int concreteFingerprint(amb({appl(prod(Symbol s, _, _), list[Tree] _), _})) = internalHashCode("amb")   + 43 * internalHashCode(t)
     when label(_, Symbol t) := s || Symbol t := s;
+int concreteFingerprint(amb({}))                                            = internalHashCode("amb");
 int concreteFingerprint(char(int ch))                                       = internalHashCode("char")  + internalHashCode(ch);
 int concreteFingerprint(cycle(Symbol s, int _))                             = internalHashCode("cycle") + 13 * internalHashCode(s);
 

diff --git a/src/org/rascalmpl/values/RascalValueFactory.java b/src/org/rascalmpl/values/RascalValueFactory.java
@@ -1052,6 +1052,10 @@ public Amb(ISet alts) {
 
 		@Override
 		public int getConcreteMatchFingerprint() {
+			if (alternatives.isEmpty()) {
+				return 96694;
+			}
+
 			return 96694 /* "amb".hashCode() */ + 43 * ((NonTerminalType) alternatives.getElementType()).getSymbol().hashCode();
 		}