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Fix tuple member-array index capture in Lua #1278

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Merged
Frotty merged 1 commit into from
Sep 2, 2026
Merged

Fix tuple member-array index capture in Lua #1278

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4 changes: 3 additions & 1 deletion ...rstscript/src/main/java/de/peeeq/wurstscript/translation/imtranslation/UsedVariables.java
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Original file line number Diff line number Diff line change
Expand Up @@ -66,7 +66,9 @@ private void handleLExprReads(ImLExpr expr) {
if (expr instanceof ImVarAccess) {
// Write only, skip
} else if (expr instanceof ImMemberAccess) {
((ImMemberAccess) expr).getReceiver().accept(this);
ImMemberAccess memberAccess = (ImMemberAccess) expr;
memberAccess.getReceiver().accept(this);
memberAccess.getIndexes().accept(this);
} else if (expr instanceof ImVarArrayAccess) {
((ImVarArrayAccess) expr).getIndexes().accept(this);
} else if (expr instanceof ImTupleSelection) {
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27 changes: 27 additions & 0 deletions de.peeeq.wurstscript/src/test/java/tests/wurstscript/tests/LuaBackendAuditTests.java
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Original file line number Diff line number Diff line change
Expand Up @@ -199,6 +199,33 @@ public void tuplesAreScalarizedWithoutLuaAllocations() throws IOException {
assertFalse("tuple arrays must be split into scalar arrays", compiled.contains("__wurst_arrIndex("));
}

@Test
public void tupleMemberArrayAssignmentCapturesIndex() throws IOException {
test().testLua(true).luaOnly(false).executeProg().lines(
"package Test",
"native testSuccess()",
"tuple pair(int first, int second)",
"constant SIZE = 10",
"class Container",
" pair array[SIZE] values",
" int used",
" function add(pair value)",
" values[used] = value",
" used++",
"init",
" let container = new Container()",
" container.add(pair(1, 2))",
" if container.used == 1 and container.values[0] == pair(1, 2)",
" testSuccess()"
);

String compiled = compiledLua("tupleMemberArrayAssignmentCapturesIndex");
assertTrue("tuple member-array index must be captured into a declared Lua local",
compiled.contains("local tuple_lvalue_index = 0"));
assertTrue("tuple member-array index capture must survive dead-store elimination",
compiled.contains("tuple_lvalue_index = Container_used_storage[this]"));
}

@Test
public void optimizedTupleCommonPathIsOnlyScalarCode() {
String compiled = compileOptimizedLua(
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