checker: fix panic on wrong arg count with or-block containing if-expr

vlib/v/checker/fn.v

@@ -1517,7 +1517,10 @@ fn (mut c Checker) fn_call(mut node ast.CallExpr, mut continue_check &bool) ast.
 				}
 			}
 		}
-		c.check_expected_arg_count(mut node, func) or { return func.return_type }
+		c.check_expected_arg_count(mut node, func) or {
+			node.return_type = func.return_type
+			return func.return_type
+		}
 	}
 	// println / eprintln / panic can print anything
 	if args_len > 0 && fn_name in print_everything_fns {

vlib/v/checker/tests/surplus_args_with_or_block_err.out

@@ -0,0 +1,9 @@
+vlib/v/checker/tests/surplus_args_with_or_block_err.vv:34:47: error: expected 2 arguments, but got 3
+   32 |
+   33 |     if config.output_file != '' {
+   34 |         export_results(results, config.output_file, config) or {
+      |                                                     ~~~~~~
+   35 |             if config.use_color {
+   36 |                 eprintln('Error: export failed')
+Details: have ([]main.SimResult, string, main.Config)
+         want ([]main.SimResult, main.Config)

vlib/v/checker/tests/surplus_args_with_or_block_err.vv

@@ -0,0 +1,42 @@
+struct Config {
+	use_color   bool
+	output_file string
+}
+
+struct SimResult {
+	filename string
+	accuracy f64
+}
+
+fn export_results(results []SimResult, config Config) ! {
+	if config.output_file == '' {
+		return
+	}
+	println('Exporting to ${config.output_file}')
+}
+
+fn run_simulation(config Config) []SimResult {
+	return [SimResult{
+		filename: 'test'
+		accuracy: 0.9
+	}]
+}
+
+fn main() {
+	mut config := Config{
+		use_color:   true
+		output_file: 'results.json'
+	}
+
+	results := run_simulation(config)
+
+	if config.output_file != '' {
+		export_results(results, config.output_file, config) or {
+			if config.use_color {
+				eprintln('Error: export failed')
+			} else {
+				eprintln('Error')
+			}
+		}
+	}
+}