support doc function nullable param

Author: CppCXY

crates/emmylua_code_analysis/src/compilation/analyzer/doc/infer_type.rs

@@ -342,8 +342,14 @@ fn infer_func_type(analyzer: &mut DocAnalyzer, func: LuaDocFuncType) -> LuaType
             continue;
         };
 
+        let nullable = param.is_nullable();
+
         let type_ref = if let Some(type_ref) = param.get_type() {
-            Some(infer_type(analyzer, type_ref))
+            let mut typ = infer_type(analyzer, type_ref);
+            if nullable && !typ.is_optional() {
+                typ = TypeOps::Union.apply(&typ, &LuaType::Nil);
+            }
+            Some(typ)
         } else {
             None
         };

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

@@ -0,0 +1,20 @@
+#[cfg(test)]
+mod test {
+    use crate::{DiagnosticCode, VirtualWorkspace};
+
+    #[test]
+    fn test_issue_98() {
+        let mut ws = VirtualWorkspace::new();
+
+        assert!(ws.check_code_for(
+            DiagnosticCode::MissingParameter,
+            r#"
+        ---@param callback fun(i?: integer)
+        function foo(callback)
+            callback()
+            callback(1123)
+        end
+        "#
+        ));
+    }
+}

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

@@ -1,2 +1,3 @@
 mod await_in_sync_test;
-mod param_type_check_test;
+mod param_type_check_test;
+mod missing_parameter_test;

crates/emmylua_parser/src/grammar/doc/types.rs

@@ -264,6 +264,7 @@ fn parse_typed_param(p: &mut LuaDocParser) -> ParseResult {
         }
         LuaTokenKind::TkDots => {
             p.bump();
+            if_token_bump(p, LuaTokenKind::TkDocQuestion);
         }
         _ => {
             return Err(LuaParseError::from_source_range(

crates/emmylua_parser/src/syntax/node/doc/types.rs

@@ -260,6 +260,10 @@ impl LuaDocTypeParam {
     pub fn get_type(&self) -> Option<LuaDocType> {
         self.child()
     }
+
+    pub fn is_nullable(&self) -> bool {
+        self.token_by_kind(LuaTokenKind::TkDocQuestion).is_some()
+    }
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]