diagnostic: fix #242

Author: xuhuanzy

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

@@ -390,6 +390,10 @@ impl LuaModuleIndex {
         file_ids
     }
 
+    pub fn is_std(&self, file_id: &FileId) -> bool {
+        self.get_std_file_ids().contains(file_id)
+    }
+
     pub fn get_main_workspace_file_ids(&self) -> Vec<FileId> {
         let mut file_ids = Vec::new();
         for module_info in self.file_module_map.values() {

crates/emmylua_code_analysis/src/diagnostic/checker/return_type_mismatch.rs

@@ -1,9 +1,9 @@
-use emmylua_parser::{LuaAstNode, LuaClosureExpr, LuaReturnStat};
-use rowan::TextRange;
+use emmylua_parser::{LuaAstNode, LuaClosureExpr, LuaExpr, LuaReturnStat};
+use rowan::{NodeOrToken, TextRange};
 
 use crate::{
-    humanize_type, DiagnosticCode, LuaSignatureId, LuaType, RenderLevel, SemanticModel,
-    SignatureReturnStatus, TypeCheckFailReason, TypeCheckResult,
+    humanize_type, DiagnosticCode, LuaSemanticDeclId, LuaSignatureId, LuaType, RenderLevel,
+    SemanticModel, SignatureReturnStatus, TypeCheckFailReason, TypeCheckResult,
 };
 
 use super::{get_own_return_stats, DiagnosticContext};
@@ -46,7 +46,12 @@ fn check_return_stat(
             &return_stat.get_expr_list().collect::<Vec<_>>(),
             None,
         )?;
-        let return_expr_types = infos.iter().map(|(typ, _)| typ.clone()).collect::<Vec<_>>();
+        let mut return_expr_types = infos.iter().map(|(typ, _)| typ.clone()).collect::<Vec<_>>();
+        // 解决 setmetatable 的返回值类型问题
+        let setmetatable_index = has_setmetatable(semantic_model, return_stat);
+        if let Some(setmetatable_index) = setmetatable_index {
+            return_expr_types[setmetatable_index] = LuaType::Any;
+        }
         let return_expr_ranges = infos
             .iter()
             .map(|(_, range)| range.clone())
@@ -59,7 +64,6 @@ fn check_return_stat(
             if return_expr_types.len() < index {
                 break;
             }
-
             check_variadic_return_type_match(
                 context,
                 semantic_model,
@@ -173,3 +177,31 @@ fn add_type_check_diagnostic(
         },
     }
 }
+
+fn has_setmetatable(semantic_model: &SemanticModel, return_stat: &LuaReturnStat) -> Option<usize> {
+    for (index, expr) in return_stat.get_expr_list().enumerate() {
+        if let LuaExpr::CallExpr(call_expr) = expr {
+            if let Some(prefix_expr) = call_expr.get_prefix_expr() {
+                let semantic_info = semantic_model
+                    .get_semantic_info(NodeOrToken::Node(prefix_expr.syntax().clone().into()))?;
+
+                if let Some(LuaSemanticDeclId::LuaDecl(decl_id)) = semantic_info.semantic_decl {
+                    let decl = semantic_model.get_db().get_decl_index().get_decl(&decl_id);
+
+                    if let Some(decl) = decl {
+                        if decl.is_global()
+                            && semantic_model
+                                .get_db()
+                                .get_module_index()
+                                .is_std(&decl.get_file_id())
+                            && decl.get_name() == "setmetatable"
+                        {
+                            return Some(index);
+                        }
+                    }
+                }
+            }
+        }
+    }
+    None
+}

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

@@ -2,6 +2,43 @@
 mod tests {
     use crate::{DiagnosticCode, VirtualWorkspace};
 
+    #[test]
+    fn test_issue_242() {
+        let mut ws = VirtualWorkspace::new_with_init_std_lib();
+
+        assert!(ws.check_code_for_namespace(
+            DiagnosticCode::ReturnTypeMismatch,
+            r#"
+                local setmetatable = setmetatable
+                --- @class A
+                local A = {}
+
+                function A:method() end
+
+                --- @return A
+                function new()
+                return setmetatable({}, { __index = A })
+                end
+        "#
+        ));
+
+        assert!(ws.check_code_for_namespace(
+            DiagnosticCode::ReturnTypeMismatch,
+            r#"
+                --- @class A
+                local A = {}
+                A.__index = A
+
+                function A:method() end
+
+                --- @return A
+                function new()
+                return setmetatable({}, A)
+                end
+        "#
+        ));
+    }
+
     #[test]
     fn test_issue_220() {
         let mut ws = VirtualWorkspace::new();