add GlobalInNonModule cheker

Fix #740

Author: CppCXY

crates/emmylua_code_analysis/resources/schema.json

@@ -430,6 +430,11 @@
           "description": "readonly",
           "type": "string",
           "const": "read-only"
+        },
+        {
+          "description": "Global variable defined in non-module scope",
+          "type": "string",
+          "const": "global-in-non-module"
         }
       ]
     },

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

@@ -0,0 +1,74 @@
+use emmylua_parser::{LuaAssignStat, LuaAst, LuaAstNode, LuaBlock, LuaVarExpr};
+
+use crate::{DiagnosticCode, LuaDeclId, SemanticModel};
+
+use super::{Checker, DiagnosticContext};
+
+pub struct GlobalInNonModuleChecker;
+
+impl Checker for GlobalInNonModuleChecker {
+    const CODES: &[DiagnosticCode] = &[DiagnosticCode::GlobalInNonModule];
+
+    fn check(context: &mut DiagnosticContext, semantic_model: &SemanticModel) {
+        let root = semantic_model.get_root().clone();
+        for assign_stat in root.descendants::<LuaAssignStat>() {
+            check_assign_stat(context, semantic_model, assign_stat);
+        }
+    }
+}
+
+fn check_assign_stat(
+    context: &mut DiagnosticContext,
+    semantic_model: &SemanticModel,
+    assign_stat: LuaAssignStat,
+) -> Option<()> {
+    let file_id = semantic_model.get_file_id();
+
+    let (vars, _) = assign_stat.get_var_and_expr_list();
+    for var in vars {
+        let decl_id = LuaDeclId::new(file_id, var.get_position());
+        if let Some(decl) = semantic_model.get_db().get_decl_index().get_decl(&decl_id)
+            && decl.is_global()
+            && is_global_define_in_non_module_scope(semantic_model, var.clone(), decl_id)
+        {
+            context.add_diagnostic(
+                DiagnosticCode::GlobalInNonModule,
+                var.get_range(),
+                t!("Global variable should only be defined in module scope").to_string(),
+                None,
+            );
+        }
+    }
+
+    Some(())
+}
+
+fn is_global_define_in_non_module_scope(
+    semantic_model: &SemanticModel,
+    var: LuaVarExpr,
+    decl_id: LuaDeclId,
+) -> bool {
+    for block in var.ancestors::<LuaBlock>() {
+        let parent = block.get_parent::<LuaAst>();
+        match parent {
+            Some(LuaAst::LuaChunk(_)) => {
+                return false;
+            }
+            Some(LuaAst::LuaClosureExpr(_)) => {
+                break;
+            }
+            _ => {}
+        }
+    }
+
+    let name = var.get_text();
+    let Some(global_id) = semantic_model
+        .get_db()
+        .get_global_index()
+        .resolve_global_decl_id(semantic_model.get_db(), &name)
+    else {
+        return true;
+    };
+
+    global_id == decl_id
+}

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

@@ -17,6 +17,7 @@ mod duplicate_require;
 mod duplicate_type;
 mod enum_value_mismatch;
 mod generic;
+mod global_in_non_module;
 mod incomplete_signature_doc;
 mod local_const_reassign;
 mod missing_fields;
@@ -120,6 +121,7 @@ pub fn check_file(context: &mut DiagnosticContext, semantic_model: &SemanticMode
         semantic_model,
     );
     run_check::<readonly_check::ReadOnlyChecker>(context, semantic_model);
+    run_check::<global_in_non_module::GlobalInNonModuleChecker>(context, semantic_model);
     Some(())
 }
 

crates/emmylua_code_analysis/src/diagnostic/lua_diagnostic_code.rs

@@ -105,6 +105,8 @@ pub enum DiagnosticCode {
     PreferredLocalAlias,
     /// readonly
     ReadOnly,
+    /// Global variable defined in non-module scope
+    GlobalInNonModule,
 
     #[serde(other)]
     None,

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

@@ -0,0 +1,17 @@
+#[cfg(test)]
+mod tests {
+    use crate::{DiagnosticCode, VirtualWorkspace};
+
+    #[test]
+    fn test_global_in_non_module() {
+        let mut ws = VirtualWorkspace::new();
+        assert!(!ws.check_code_for(
+            DiagnosticCode::GlobalInNonModule,
+            r#"
+            local function name()
+                bbbb = 123
+            end
+        "#
+        ));
+    }
+}

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

@@ -10,6 +10,7 @@ mod duplicate_index_test;
 mod duplicate_require_test;
 mod enum_value_mismatch_test;
 mod generic_constraint_mismatch_test;
+mod global_in_non_module_test;
 mod incomplete_signature_doc_test;
 mod inject_field_test;
 mod missing_fields_test;