From 3ee3c8b3eda93bf8c014de78154928ffe24f4fd8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20D=C3=A4schle?= <daniel.daeschle@gmail.com>
Date: Wed, 30 Dec 2020 20:18:36 +0100
Subject: [PATCH] parser: proper error on fn decl in script mode (#7680)

---
 vlib/v/parser/fn.v                                 | 5 +++++
 vlib/v/parser/tests/invalid_fn_decl_script_err.out | 7 +++++++
 vlib/v/parser/tests/invalid_fn_decl_script_err.vv  | 5 +++++
 3 files changed, 17 insertions(+)
 create mode 100644 vlib/v/parser/tests/invalid_fn_decl_script_err.out
 create mode 100644 vlib/v/parser/tests/invalid_fn_decl_script_err.vv

diff --git a/vlib/v/parser/fn.v b/vlib/v/parser/fn.v
index c18ec96fb6..162e895493 100644
--- a/vlib/v/parser/fn.v
+++ b/vlib/v/parser/fn.v
@@ -424,6 +424,11 @@ fn (mut p Parser) fn_decl() ast.FnDecl {
 fn (mut p Parser) anon_fn() ast.AnonFn {
 	pos := p.tok.position()
 	p.check(.key_fn)
+	if p.pref.is_script && p.tok.kind == .name {
+		p.error_with_pos('function declarations in script mode should be before all script statements',
+			p.tok.position())
+		return ast.AnonFn{}
+	}
 	p.open_scope()
 	// TODO generics
 	args, _, is_variadic := p.fn_args()
diff --git a/vlib/v/parser/tests/invalid_fn_decl_script_err.out b/vlib/v/parser/tests/invalid_fn_decl_script_err.out
new file mode 100644
index 0000000000..aead2d093f
--- /dev/null
+++ b/vlib/v/parser/tests/invalid_fn_decl_script_err.out
@@ -0,0 +1,7 @@
+vlib/v/parser/tests/invalid_fn_decl_script_err.vv:3:4: error: function declarations in script mode should be before all script statements
+    1 | mynum := 10
+    2 |
+    3 | fn main() {
+      |    ~~~~
+    4 |     println(mynum)
+    5 | }
\ No newline at end of file
diff --git a/vlib/v/parser/tests/invalid_fn_decl_script_err.vv b/vlib/v/parser/tests/invalid_fn_decl_script_err.vv
new file mode 100644
index 0000000000..196895a1cf
--- /dev/null
+++ b/vlib/v/parser/tests/invalid_fn_decl_script_err.vv
@@ -0,0 +1,5 @@
+mynum := 10
+
+fn main() {
+	println(mynum)
+}