Fix #892

Author: CppCXY

crates/emmylua_code_analysis/src/diagnostic/checker/code_style/preferred_local_alias.rs

@@ -98,8 +98,12 @@ fn collect_local_alias(
             {
                 let name_token = local_name.get_name_token()?;
                 let preferred_name = name_token.get_name_text();
+                let ref_var = match find_ref_var_decl_id(semantic_model, value_expr) {
+                    Some(id) => id,
+                    None => continue,
+                };
 
-                local_alias_set.insert(name, preferred_name.to_string(), semantic_id);
+                local_alias_set.insert(name, preferred_name.to_string(), semantic_id, ref_var);
                 local_alias_set.add_disable_check(value_expr.get_range());
             }
         }
@@ -108,6 +112,27 @@ fn collect_local_alias(
     Some(())
 }
 
+fn find_ref_var_decl_id(
+    semantic_model: &SemanticModel,
+    expr: &LuaExpr,
+) -> Option<LuaSemanticDeclId> {
+    let mut prefix = expr.clone();
+    while let LuaExpr::IndexExpr(index_expr) = prefix {
+        match index_expr.get_prefix_expr() {
+            Some(LuaExpr::NameExpr(name_expr)) => {
+                let node_or_token = NodeOrToken::Node(name_expr.syntax().clone());
+                return semantic_model.find_decl(node_or_token, SemanticDeclLevel::NoTrace);
+            }
+            Some(LuaExpr::IndexExpr(prefix_index_expr)) => {
+                prefix = LuaExpr::IndexExpr(prefix_index_expr);
+            }
+            _ => return None,
+        }
+    }
+
+    None
+}
+
 fn is_only_dot_index_expr(expr: &LuaExpr) -> Option<bool> {
     let mut index_expr = match expr {
         LuaExpr::IndexExpr(index_expr) => index_expr.clone(),
@@ -129,6 +154,19 @@ fn is_only_dot_index_expr(expr: &LuaExpr) -> Option<bool> {
     }
 }
 
+fn get_first_name_expr(expr: &LuaIndexExpr) -> Option<LuaExpr> {
+    let mut index_expr = expr.clone();
+    loop {
+        match index_expr.get_prefix_expr() {
+            Some(LuaExpr::NameExpr(name_expr)) => return Some(LuaExpr::NameExpr(name_expr)),
+            Some(LuaExpr::IndexExpr(prefix_index_expr)) => {
+                index_expr = prefix_index_expr;
+            }
+            _ => return None,
+        }
+    }
+}
+
 #[derive(Debug)]
 struct LocalAliasSet {
     local_alias_stack: Vec<HashMap<String, LocalAliasInfo>>,
@@ -137,7 +175,8 @@ struct LocalAliasSet {
 
 #[derive(Debug)]
 struct LocalAliasInfo {
-    pub decl_id: LuaSemanticDeclId,
+    pub ref_var: LuaSemanticDeclId,
+    pub ref_field: LuaSemanticDeclId,
     pub preferred_name: String,
     pub invalid: bool,
 }
@@ -158,12 +197,19 @@ impl LocalAliasSet {
         self.local_alias_stack.pop();
     }
 
-    fn insert(&mut self, name: String, preferred_name: String, decl_id: LuaSemanticDeclId) {
+    fn insert(
+        &mut self,
+        name: String,
+        preferred_name: String,
+        decl_id: LuaSemanticDeclId,
+        ref_var: LuaSemanticDeclId,
+    ) {
         if let Some(map) = self.local_alias_stack.last_mut() {
             map.insert(
                 name,
                 LocalAliasInfo {
-                    decl_id,
+                    ref_var,
+                    ref_field: decl_id,
                     preferred_name,
                     invalid: false,
                 },
@@ -230,29 +276,40 @@ fn check_index_expr_preference(
         return Some(());
     }
 
-    if semantic_model.is_reference_to(
+    let var_expr = get_first_name_expr(index_expr)?;
+    if !semantic_model.is_reference_to(
+        var_expr.syntax().clone(),
+        alias_info.ref_var.clone(),
+        SemanticDeclLevel::NoTrace,
+    ) {
+        return Some(());
+    }
+
+    if !semantic_model.is_reference_to(
         index_expr.syntax().clone(),
-        alias_info.decl_id.clone(),
+        alias_info.ref_field.clone(),
         SemanticDeclLevel::NoTrace,
     ) {
-        if mutable_index {
-            alias_info.invalid = true;
-            return Some(());
-        }
+        return Some(());
+    }
 
-        context.add_diagnostic(
-            DiagnosticCode::PreferredLocalAlias,
-            index_expr.get_range(),
-            t!(
-                "Prefer use local alias variable '%{name}'",
-                name = alias_info.preferred_name
-            )
-            .to_string(),
-            Some(json!({
-                "preferredAlias": alias_info.preferred_name.clone(),
-            })),
-        );
+    if mutable_index {
+        alias_info.invalid = true;
+        return Some(());
     }
 
+    context.add_diagnostic(
+        DiagnosticCode::PreferredLocalAlias,
+        index_expr.get_range(),
+        t!(
+            "Prefer use local alias variable '%{name}'",
+            name = alias_info.preferred_name
+        )
+        .to_string(),
+        Some(json!({
+            "preferredAlias": alias_info.preferred_name.clone(),
+        })),
+    );
+
     Some(())
 }