Auto merge of rust-lang#16493 - Young-Flash:method_call_parser, r=Veykril

fix: emit parser error for missing argument list

close rust-lang/rust-analyzer#16362

Author: bors

crates/parser/src/grammar/expressions.rs

@@ -530,6 +530,15 @@ fn method_call_expr<const FLOAT_RECOVERY: bool>(
     generic_args::opt_generic_arg_list(p, true);
     if p.at(T!['(']) {
         arg_list(p);
+    } else {
+        // emit an error when argument list is missing
+
+        // test_err method_call_missing_argument_list
+        // fn func() {
+        //     foo.bar::<>
+        //     foo.bar::<i32>;
+        // }
+        p.error("expected argument list");
     }
     m.complete(p, METHOD_CALL_EXPR)
 }

crates/parser/test_data/parser/inline/err/0028_method_call_missing_argument_list.rast

@@ -0,0 +1,56 @@
+SOURCE_FILE
+  FN
+    FN_KW "fn"
+    WHITESPACE " "
+    NAME
+      IDENT "func"
+    PARAM_LIST
+      L_PAREN "("
+      R_PAREN ")"
+    WHITESPACE " "
+    BLOCK_EXPR
+      STMT_LIST
+        L_CURLY "{"
+        WHITESPACE "\n    "
+        EXPR_STMT
+          METHOD_CALL_EXPR
+            PATH_EXPR
+              PATH
+                PATH_SEGMENT
+                  NAME_REF
+                    IDENT "foo"
+            DOT "."
+            NAME_REF
+              IDENT "bar"
+            GENERIC_ARG_LIST
+              COLON2 "::"
+              L_ANGLE "<"
+              R_ANGLE ">"
+        WHITESPACE "\n    "
+        EXPR_STMT
+          METHOD_CALL_EXPR
+            PATH_EXPR
+              PATH
+                PATH_SEGMENT
+                  NAME_REF
+                    IDENT "foo"
+            DOT "."
+            NAME_REF
+              IDENT "bar"
+            GENERIC_ARG_LIST
+              COLON2 "::"
+              L_ANGLE "<"
+              TYPE_ARG
+                PATH_TYPE
+                  PATH
+                    PATH_SEGMENT
+                      NAME_REF
+                        IDENT "i32"
+              R_ANGLE ">"
+          SEMICOLON ";"
+        WHITESPACE "\n"
+        R_CURLY "}"
+  WHITESPACE "\n"
+error 27: expected argument list
+error 27: expected SEMICOLON
+error 46: expected argument list

crates/parser/test_data/parser/inline/err/0028_method_call_missing_argument_list.rs

@@ -0,0 +1,4 @@
+fn func() {
+    foo.bar::<>
+    foo.bar::<i32>;
+}