Preserve tuple calls for component selection

Author: Frotty

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

@@ -198,7 +198,10 @@ public void visit(ImTupleSelection ts) {
                     te.setParent(null);
                     if (i != ti) {
                         // if not the thing we want to return, just keep it in statements for side-effects
-                        extractSideEffect(te, stmts);
+                        ImExpr remaining = extractSideEffect(te, stmts);
+                        if (SideEffectAnalyzer.quickcheckHasSideeffects(remaining)) {
+                            stmts.add(remaining);
+                        }
                     } else { // if it is the part we want to return ...
                         result = extractSideEffect(te, stmts);
                     }

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

@@ -169,6 +169,28 @@ public void tupleReturningCallsAreCapturedBeforeComparison() throws IOException
         assertFalse(compiled.contains("tupleEquals"));
     }
 
+    @Test
+    public void selectingLaterTupleComponentStillInvokesProducer() throws IOException {
+        test().testLua(true).executeProg().lines(
+            "package Test",
+            "native testSuccess()",
+            "tuple pair(int x, int y)",
+            "class Producer",
+            "    int calls",
+            "    @noinline function produce(int seed) returns pair",
+            "        calls++",
+            "        return pair(seed, seed + calls)",
+            "init",
+            "    let producer = new Producer()",
+            "    let selected = producer.produce(5).y",
+            "    if selected == 6 and producer.calls == 1",
+            "        testSuccess()"
+        );
+
+        String compiled = compiledLua("selectingLaterTupleComponentStillInvokesProducer");
+        assertFalse(compiled.contains("tupleCopy"));
+    }
+
     @Test
     public void compiletimeGenericArrayReplayLeavesAreSplit() {
         String compiled = compileLuaWithRunArgs(