Bug fix in integer power type checking.

git-svn-id: https://www.prismmodelchecker.org/svn/prism/prism/trunk@2205 bbc10eb1-c90d-0410-af57-cb519fbb1720

prism/src/parser/ast/ExpressionFunc.java

@@ -253,7 +253,7 @@ public class ExpressionFunc extends Expression
 		double base = getOperand(0).evaluateDouble(ec);
 		double exp = getOperand(1).evaluateDouble(ec);
 		// Not allowed to do e.g. pow(2,-2) because of typing (should be pow(2.0,-2) instead)
-		if (type instanceof TypeInt || (exp < 0))
+		if (type instanceof TypeInt && (exp < 0))
 			throw new PrismLangException("Negative exponent not allowed for integer power", this);
 		double res = Math.pow(base, exp);
 		if (type instanceof TypeInt) {