fix tuple type check issue

Author: Frotty

de.peeeq.wurstscript/src/main/java/de/peeeq/wurstscript/translation/imtranslation/EliminateTuples.java

@@ -567,9 +567,8 @@ private static ImStatementExpr inReturn(ImReturn parent, ImTupleExpr tupleExpr,
 
         // Sanity:
         if (flatExprs.size() != returnVars.size()) {
-            throw new RuntimeException("Tuple arity mismatch in return: RHS has "
-                + flatExprs.size() + " leaves, but function expects "
-                + returnVars.size());
+            throw new CompileError(parent.getTrace(),
+                "Cannot return tuple with " + flatExprs.size() + " element(s) from function expecting " + returnVars.size() + " element(s)");
         }
 
         // 2) Assign per component, converting nulls to proper defaults of LHS type

de.peeeq.wurstscript/src/test/java/tests/wurstscript/tests/TupleTests.java

@@ -539,6 +539,21 @@ public void nullStringInTuple() {
                 "        testSuccess()"
         );
     }
+    @Test
+    public void returnWrongTupleType() {
+        testAssertErrorsLines(false, "Cannot return t2",
+                "package test",
+                "native testSuccess()",
+                "tuple t1(int i, int i2)",
+                "tuple t2(int i, int i2, int i3)",
+                "let t2i = t2(1, 2, 3)",
+                "function foo() returns t1",
+                "    return t2i",
+                "init",
+                "    let x = foo()"
+        );
+    }
+
     @Test
     public void nestedTupleArray() {
         testAssertOkLines(true,