From b20777df59ac3f609a3f42dbca468dd00194ac0a Mon Sep 17 00:00:00 2001
From: yuyi <yuyi98@163.com>
Date: Tue, 28 Apr 2020 13:21:50 +0800
Subject: [PATCH] checker: main function called error

---
 vlib/v/checker/checker.v                 | 3 +++
 vlib/v/checker/tests/main_called_err.out | 5 +++++
 vlib/v/checker/tests/main_called_err.v   | 3 +++
 vlib/v/checker/tests/main_called_err.vv  | 3 +++
 4 files changed, 14 insertions(+)
 create mode 100644 vlib/v/checker/tests/main_called_err.out
 create mode 100644 vlib/v/checker/tests/main_called_err.v
 create mode 100644 vlib/v/checker/tests/main_called_err.vv

diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 7ef277e4d9..724b83d3d1 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -677,6 +677,9 @@ pub fn (mut c Checker) call_fn(call_expr mut ast.CallExpr) table.Type {
 		c.returns = true
 	}
 	fn_name := call_expr.name
+	if fn_name == 'main' {
+		c.error('the `main` function cannot be called in the program', call_expr.pos)
+	}
 	if fn_name == 'typeof' {
 		// TODO: impl typeof properly (probably not going to be a fn call)
 		return table.string_type
diff --git a/vlib/v/checker/tests/main_called_err.out b/vlib/v/checker/tests/main_called_err.out
new file mode 100644
index 0000000000..df9319b17c
--- /dev/null
+++ b/vlib/v/checker/tests/main_called_err.out
@@ -0,0 +1,5 @@
+vlib/v/checker/tests/main_called_err.v:2:2: error: the `main` function cannot be called in the program
+    1| fn main() {
+    2|     main()
+           ~~~~~~
+    3| }
diff --git a/vlib/v/checker/tests/main_called_err.v b/vlib/v/checker/tests/main_called_err.v
new file mode 100644
index 0000000000..2be2db12ba
--- /dev/null
+++ b/vlib/v/checker/tests/main_called_err.v
@@ -0,0 +1,3 @@
+fn main() {
+	main()
+}
diff --git a/vlib/v/checker/tests/main_called_err.vv b/vlib/v/checker/tests/main_called_err.vv
new file mode 100644
index 0000000000..2be2db12ba
--- /dev/null
+++ b/vlib/v/checker/tests/main_called_err.vv
@@ -0,0 +1,3 @@
+fn main() {
+	main()
+}