support multi line union completion

Fix #792

Author: CppCXY

crates/emmylua_code_analysis/src/semantic/infer/infer_index.rs

@@ -170,6 +170,14 @@ pub fn infer_member_by_member_key(
         LuaType::Union(union_type) => {
             infer_union_member(db, cache, union_type, index_expr, infer_guard)
         }
+        LuaType::MultiLineUnion(multi_union) => {
+            let union_type = multi_union.to_union();
+            if let LuaType::Union(union_type) = union_type {
+                infer_union_member(db, cache, &union_type, index_expr, infer_guard)
+            } else {
+                Err(InferFailReason::FieldNotFound)
+            }
+        }
         LuaType::Intersection(intersection_type) => {
             infer_intersection_member(db, cache, intersection_type, index_expr, infer_guard)
         }
@@ -641,7 +649,14 @@ fn infer_union_member(
     infer_guard: &InferGuardRef,
 ) -> InferResult {
     let mut member_types = Vec::new();
+    let mut meet_string = false;
     for sub_type in union_type.into_vec() {
+        if sub_type.is_string() {
+            if meet_string {
+                continue;
+            }
+            meet_string = true;
+        }
         let result = infer_member_by_member_key(
             db,
             cache,

crates/emmylua_code_analysis/src/semantic/member/find_members.rs

@@ -78,6 +78,14 @@ fn find_members_guard(
         LuaType::Tuple(tuple_type) => find_tuple_members(tuple_type, filter),
         LuaType::Object(object_type) => find_object_members(object_type, filter),
         LuaType::Union(union_type) => find_union_members(db, union_type, infer_guard, filter),
+        LuaType::MultiLineUnion(multi_union) => {
+            let union_type = multi_union.to_union();
+            if let LuaType::Union(union_type) = union_type {
+                find_union_members(db, &union_type, infer_guard, filter)
+            } else {
+                None
+            }
+        }
         LuaType::Intersection(intersection_type) => {
             find_intersection_members(db, intersection_type, infer_guard, filter)
         }
@@ -282,7 +290,15 @@ fn find_union_members(
     filter: &FindMemberFilter,
 ) -> FindMembersResult {
     let mut members = Vec::new();
+    let mut meet_string = false;
     for typ in union_type.into_vec().iter() {
+        if typ.is_string() {
+            if meet_string {
+                continue;
+            }
+            meet_string = true;
+        }
+
         let sub_members = find_members_guard(db, typ, &infer_guard.fork(), filter);
         if let Some(sub_members) = sub_members {
             members.extend(sub_members);

crates/emmylua_code_analysis/src/semantic/member/mod.rs

@@ -22,9 +22,10 @@ use super::{
 
 pub fn get_buildin_type_map_type_id(type_: &LuaType) -> Option<LuaTypeDeclId> {
     match type_ {
-        LuaType::String | LuaType::StringConst(_) | LuaType::DocStringConst(_) => {
-            Some(LuaTypeDeclId::new("string"))
-        }
+        LuaType::String
+        | LuaType::StringConst(_)
+        | LuaType::DocStringConst(_)
+        | LuaType::Language(_) => Some(LuaTypeDeclId::new("string")),
         LuaType::Io => Some(LuaTypeDeclId::new("io")),
         _ => None,
     }