update

Author: CppCXY

crates/emmylua_code_analysis/src/semantic/infer/narrow/condition_flow/binary_flow.rs

@@ -191,7 +191,7 @@ fn maybe_type_guard_binary(
 
     let result_type = match condition_flow {
         InferConditionFlow::TrueCondition => {
-            narrow_down_type(db, antecedent_type.clone(), narrow).unwrap_or(antecedent_type)
+            narrow_down_type(db, antecedent_type.clone(), narrow.clone()).unwrap_or(narrow)
         }
         InferConditionFlow::FalseCondition => TypeOps::Remove.apply(db, &antecedent_type, &narrow),
     };
@@ -231,8 +231,8 @@ fn maybe_var_eq_narrow(
 
             let result_type = match condition_flow {
                 InferConditionFlow::TrueCondition => {
-                    narrow_down_type(db, antecedent_type.clone(), right_expr_type)
-                        .unwrap_or(antecedent_type)
+                    narrow_down_type(db, antecedent_type, right_expr_type.clone())
+                        .unwrap_or(right_expr_type)
                 }
                 InferConditionFlow::FalseCondition => {
                     TypeOps::Remove.apply(db, &antecedent_type, &right_expr_type)
@@ -287,8 +287,8 @@ fn maybe_var_eq_narrow(
 
             let result_type = match condition_flow {
                 InferConditionFlow::TrueCondition => {
-                    narrow_down_type(db, antecedent_type.clone(), right_expr_type)
-                        .unwrap_or(antecedent_type)
+                    narrow_down_type(db, antecedent_type, right_expr_type.clone())
+                        .unwrap_or(right_expr_type)
                 }
                 InferConditionFlow::FalseCondition => {
                     TypeOps::Remove.apply(db, &antecedent_type, &right_expr_type)

crates/emmylua_code_analysis/src/semantic/infer/narrow/get_type_at_flow.rs

@@ -214,7 +214,7 @@ fn get_type_at_assign_stat(
             get_type_at_flow(db, tree, cache, root, var_ref_id, antecedent_flow_id)?;
 
         return Ok(ResultTypeOrContinue::Result(
-            narrow_down_type(db, antecedent_type.clone(), expr_type).unwrap_or(antecedent_type),
+            narrow_down_type(db, antecedent_type, expr_type.clone()).unwrap_or(expr_type),
         ));
     }
 

crates/emmylua_code_analysis/src/semantic/infer/narrow/narrow_type/mod.rs

@@ -1,6 +1,8 @@
 mod false_or_nil_type;
 
-use crate::{get_real_type, DbIndex, LuaType, LuaUnionType, TypeOps};
+use crate::{
+    get_real_type, semantic::type_check::is_sub_type_of, DbIndex, LuaType, LuaUnionType, TypeOps,
+};
 pub use false_or_nil_type::{narrow_false_or_nil, remove_false_or_nil};
 
 // need to be optimized
@@ -10,7 +12,6 @@ pub fn narrow_down_type(db: &DbIndex, source: LuaType, target: LuaType) -> Optio
     }
 
     let real_source_ref = get_real_type(db, &source).unwrap_or(&source);
-    let mut opt_result = None;
     match &target {
         LuaType::Number => {
             if real_source_ref.is_number() {
@@ -160,9 +161,16 @@ pub fn narrow_down_type(db: &DbIndex, source: LuaType, target: LuaType) -> Optio
             return Some(result_type);
         }
         LuaType::Variadic(_) => return Some(source),
-        _ => {
-            opt_result = Some(source.clone());
-        }
+        LuaType::Def(type_id) | LuaType::Ref(type_id) => match real_source_ref {
+            LuaType::Def(ref_id) | LuaType::Ref(ref_id) => {
+                if is_sub_type_of(db, ref_id, type_id) || is_sub_type_of(db, type_id, ref_id) {
+                    return Some(source);
+                }
+            }
+            _ => {}
+        },
+
+        _ => {}
     }
 
     match real_source_ref {
@@ -183,5 +191,5 @@ pub fn narrow_down_type(db: &DbIndex, source: LuaType, target: LuaType) -> Optio
         _ => {}
     }
 
-    opt_result
+    None
 }