diff --git a/prism/src/parser/visitor/TypeCheck.java b/prism/src/parser/visitor/TypeCheck.java
index 778a9cbb..187ee59e 100644
--- a/prism/src/parser/visitor/TypeCheck.java
+++ b/prism/src/parser/visitor/TypeCheck.java
@@ -371,12 +371,19 @@ public class TypeCheck extends ASTTraverse
 			}
 			break;
 		case ExpressionFunc.MULTI:
-			// All operands must be booleans or doubles
+			// All operands must be booleans or doubles, and doubles must come first.
+			boolean seenBoolean = false;
 			for (i = 0; i < n; i++) {
 				if (!(types[i] instanceof TypeBool || types[i] instanceof TypeDouble)) {
 					throw new PrismLangException("Type error: non-Boolean/Double argument to  function \"" + e.getName()
 							+ "\"", e.getOperand(i));
 				}
+				if (seenBoolean && types[i] instanceof TypeDouble) {
+					throw new PrismLangException("Type error: in the function \"" + e.getName() + "\", any Double arguments must come before any Boolean arguments.");
+				}
+				if (types[i] instanceof TypeBool) {
+					seenBoolean = true;
+				}
 			}
 			break;
 		default: