checker, cgen: fix go print (#15927)

Author: yuyi98

vlib/v/checker/fn.v

@@ -855,6 +855,7 @@ pub fn (mut c Checker) fn_call(mut node ast.CallExpr, mut continue_check &bool)
 		c.fail_if_unreadable(arg.expr, arg.typ, 'argument to print')
 		c.inside_println_arg = false
 		node.return_type = ast.void_type
+		c.set_node_expected_arg_types(mut node, func)
 		/*
 		// TODO: optimize `struct T{} fn (t &T) str() string {return 'abc'} mut a := []&T{} a << &T{} println(a[0])`
 		// It currently generates:

vlib/v/gen/c/fn.v

@@ -2057,6 +2057,19 @@ fn (mut g Gen) go_expr(node ast.GoExpr) {
 				}
 				call_args_str = call_args_str.replace_each(rep_group)
 				g.gowrappers.write_string(call_args_str)
+			} else if expr.name in ['print', 'println', 'eprint', 'eprintln', 'panic']
+				&& expr.args[0].typ != ast.string_type {
+				pos := g.out.len
+				g.gen_expr_to_string(expr.args[0].expr, expr.args[0].typ)
+				mut call_args_str := g.out.after(pos)
+				g.out.go_back(call_args_str.len)
+				mut rep_group := []string{cap: 2 * expr.args.len}
+				for i in 0 .. expr.args.len {
+					rep_group << g.expr_string(expr.args[i].expr)
+					rep_group << 'arg->arg${i + 1}'
+				}
+				call_args_str = call_args_str.replace_each(rep_group)
+				g.gowrappers.write_string(call_args_str)
 			} else {
 				for i in 0 .. expr.args.len {
 					expected_nr_muls := expr.expected_arg_types[i].nr_muls()

vlib/v/tests/inout/go_print.out

@@ -0,0 +1 @@
+[1, 2, 3]

vlib/v/tests/inout/go_print.vv

@@ -0,0 +1,4 @@
+fn main(){
+	g := go print([1, 2, 3])
+	g.wait()
+}