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Fix: undefined-field false positive for table<K,V> when value type is generic and key is not string/integer #1109

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Fix: undefined-field false positive for table<K,V> when value type is generic and key is not string/integer #1109

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5 changes: 5 additions & 0 deletions crates/emmylua_code_analysis/src/diagnostic/checker/check_field.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -274,6 +274,8 @@ pub(super) fn is_valid_member(
}
} else if typ.is_integer() && key_types.iter().any(|typ| typ.is_integer()) {
return Some(());
} else if key_types.iter().any(|kt| kt == typ) {
return Some(());
Comment on lines +277 to +278

@gemini-code-assist gemini-code-assist Bot Jun 11, 2026

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medium

Since key_types is a HashSet<LuaType>, you can use contains for an $O(1)$ lookup instead of performing a linear $O(N)$ scan with iter().any(...). This improves performance during diagnostic analysis.

Suggested change
} else if key_types.iter().any(|kt| kt == typ) {
return Some(());
} else if key_types.contains(typ) {
return Some(());

}
}
LuaMemberKey::Name(_) => {
Expand Down Expand Up @@ -378,6 +380,9 @@ fn get_key_types(db: &DbIndex, typ: &LuaType) -> HashSet<LuaType> {
LuaType::DocStringConst(_) | LuaType::DocIntegerConst(_) => {
type_set.insert(current_type);
}
LuaType::Boolean | LuaType::Thread | LuaType::Number | LuaType::Userdata => {
type_set.insert(current_type);
}
LuaType::Call(alias_call) => {
if let Some(key_types) = get_keyof_keys(db, alias_call) {
for t in key_types {
Expand Down
44 changes: 44 additions & 0 deletions crates/emmylua_code_analysis/src/diagnostic/test/undefined_field_test.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -900,4 +900,48 @@ mod test {
assert_eq!(ws.expr_ty("alias_result"), ws.ty("string?"));
assert_eq!(ws.expr_ty("numeric_result"), ws.ty("string?"));
}

#[test]
fn test_table_generic_value_with_thread_key() {
let mut ws = VirtualWorkspace::new();
assert!(ws.has_no_diagnostic(
DiagnosticCode::UndefinedField,
r#"
---@class Box<T>
---@field value T

---@class Container
---@field items table<thread, Box<unknown>?>
local Container = {}

---@param co thread
function Container:get(co)
local item = self.items[co]
return item
end
"#
));
}

#[test]
fn test_table_generic_value_with_boolean_key() {
let mut ws = VirtualWorkspace::new();
assert!(ws.has_no_diagnostic(
DiagnosticCode::UndefinedField,
r#"
---@class Box<T>
---@field value T

---@class Container
---@field items table<boolean, Box<unknown>?>
local Container = {}

---@param key boolean
function Container:get(key)
local item = self.items[key]
return item
end
"#
));
}
}
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