Fix #369

Author: xuhuanzy

crates/emmylua_code_analysis/src/compilation/test/flow.rs

@@ -561,6 +561,35 @@ end
         ));
     }
 
+    #[test]
+    fn test_issue_369() {
+        let mut ws = VirtualWorkspace::new();
+
+        ws.def(
+            r#"
+            --- @enum myenum
+            local myenum = { A = 1 }
+
+            --- @param x myenum|{}
+            function foo(x)
+                if type(x) ~= 'table' then
+                    a = x
+                else
+                    b = x
+                end
+            end
+        "#,
+        );
+
+        let a = ws.expr_ty("a");
+        let a_expected = ws.ty("myenum");
+        assert_eq!(a, a_expected);
+
+        let b = ws.expr_ty("b");
+        let b_expected = ws.ty("{}");
+        assert_eq!(b, b_expected);
+    }
+
     #[test]
     fn test_issue_405() {
         let mut ws = VirtualWorkspace::new();

crates/emmylua_code_analysis/src/db_index/type/type_ops/mod.rs

@@ -32,7 +32,7 @@ impl TypeOps {
             TypeOps::Remove => {
                 remove_type::remove_type(db, source.clone(), target.clone()).unwrap_or(LuaType::Any)
             }
-            TypeOps::Narrow => narrow_type::narrow_down_type(source.clone(), target.clone())
+            TypeOps::Narrow => narrow_type::narrow_down_type(db, source.clone(), target.clone())
                 .unwrap_or(target.clone()),
             TypeOps::And => and_type::and_type(source.clone(), target.clone()),
             _ => source.clone(),

crates/emmylua_code_analysis/src/db_index/type/type_ops/narrow_type.rs

@@ -1,7 +1,7 @@
-use crate::{LuaType, LuaUnionType};
+use crate::{DbIndex, LuaType, LuaUnionType};
 
 // need to be optimized
-pub fn narrow_down_type(source: LuaType, target: LuaType) -> Option<LuaType> {
+pub fn narrow_down_type(db: &DbIndex, source: LuaType, target: LuaType) -> Option<LuaType> {
     if source == target {
         return Some(source);
     }
@@ -31,16 +31,24 @@ pub fn narrow_down_type(source: LuaType, target: LuaType) -> Option<LuaType> {
             LuaType::TableConst(_) => {
                 return Some(source);
             }
+            LuaType::Object(_) => {
+                return Some(source);
+            }
             LuaType::Table | LuaType::Userdata | LuaType::Any | LuaType::Unknown => {
                 return Some(LuaType::Table);
             }
-            LuaType::Ref(_)
-            | LuaType::Def(_)
-            | LuaType::Global
+            LuaType::Global
             | LuaType::Array(_)
             | LuaType::Tuple(_)
             | LuaType::Generic(_)
             | LuaType::TableGeneric(_) => return Some(source),
+            LuaType::Ref(type_decl_id) | LuaType::Def(type_decl_id) => {
+                let type_decl = db.get_type_index().get_type_decl(type_decl_id)?;
+                // enum 在实际使用时实际上是 enum.field, 并不等于 table
+                if !type_decl.is_enum() {
+                    return Some(source);
+                }
+            }
             _ => {}
         },
         LuaType::Function => {
@@ -117,7 +125,7 @@ pub fn narrow_down_type(source: LuaType, target: LuaType) -> Option<LuaType> {
             | LuaType::TableGeneric(_) => return Some(source),
             _ => {}
         },
-        LuaType::Instance(base) => return narrow_down_type(source, base.get_base().clone()),
+        LuaType::Instance(base) => return narrow_down_type(db, source, base.get_base().clone()),
         LuaType::Unknown => return Some(source),
         _ => {
             if target.is_unknown() {
@@ -133,7 +141,7 @@ pub fn narrow_down_type(source: LuaType, target: LuaType) -> Option<LuaType> {
             let mut union_types = union
                 .get_types()
                 .iter()
-                .filter_map(|t| narrow_down_type(t.clone(), target.clone()))
+                .filter_map(|t| narrow_down_type(db, t.clone(), target.clone()))
                 .collect::<Vec<_>>();
 
             union_types.dedup();

crates/emmylua_code_analysis/src/db_index/type/type_ops/remove_type.rs

@@ -67,6 +67,10 @@ pub fn remove_type(db: &DbIndex, source: LuaType, removed_type: LuaType) -> Opti
             | LuaType::TableGeneric(_) => return None,
             LuaType::Ref(type_decl_id) | LuaType::Def(type_decl_id) => {
                 let type_decl = db.get_type_index().get_type_decl(type_decl_id)?;
+                // enum 在实际使用时实际上是 enum.field, 并不等于 table
+                if type_decl.is_enum() {
+                    return Some(source);
+                }
                 if type_decl.is_alias() {
                     if let Some(alias_ref) = get_real_type(db, &source) {
                         return remove_type(db, alias_ref.clone(), removed_type);

crates/emmylua_code_analysis/src/diagnostic/test/assign_type_mismatch_test.rs

@@ -822,7 +822,6 @@ return t
         "#
         ));
     }
-
     #[test]
     fn test_issue_393() {
         let mut ws = VirtualWorkspace::new();