fix flow analyze

Author: CppCXY

crates/emmylua_code_analysis/src/db_index/flow/flow_chain.rs

@@ -77,6 +77,20 @@ impl LuaFlowChain {
                 })
             })
     }
+
+    pub fn merge_chain(&mut self, chain: LuaFlowChain) {
+        if self.type_asserts.is_empty() {
+            self.type_asserts = chain.type_asserts;
+            return;
+        }
+
+        for (path, entries) in chain.type_asserts {
+            self.type_asserts
+                .entry(path)
+                .or_insert_with(Vec::new)
+                .extend(entries);
+        }
+    }
 }
 
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]

crates/emmylua_code_analysis/src/db_index/flow/mod.rs

@@ -22,10 +22,8 @@ impl LuaFlowIndex {
 
     pub fn add_flow_chain(&mut self, file_id: FileId, chain: LuaFlowChain) {
         let id = chain.get_flow_id();
-        self.chains_map
-            .entry(file_id)
-            .or_insert_with(HashMap::new)
-            .insert(id, chain);
+        let old_chain = self.get_or_create_flow_chain(file_id, id);
+        old_chain.merge_chain(chain);
     }
 
     pub fn get_flow_chain(&self, file_id: FileId, flow_id: LuaFlowId) -> Option<&LuaFlowChain> {

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

@@ -2,6 +2,10 @@ use crate::{LuaType, LuaUnionType};
 
 // need to be optimized
 pub fn narrow_down_type(source: LuaType, target: LuaType) -> Option<LuaType> {
+    if source == target {
+        return Some(source);
+    }
+
     match &target {
         LuaType::Number => {
             if source.is_number() {