checker: fix missing check for empty noreturn fn

vlib/v/checker/return.v

@@ -368,8 +368,9 @@ fn (mut c Checker) check_noreturn_fn_decl(mut node ast.FnDecl) {
 	if uses_return_stmt(node.stmts) {
 		c.error('[noreturn] functions cannot use return statements', node.pos)
 	}
+	mut pos := node.pos
+	mut is_valid_end_of_noreturn_fn := false
 	if node.stmts.len != 0 {
-		mut is_valid_end_of_noreturn_fn := false
 		last_stmt := node.stmts.last()
 		match last_stmt {
 			ast.ExprStmt {
@@ -392,11 +393,13 @@ fn (mut c Checker) check_noreturn_fn_decl(mut node ast.FnDecl) {
 			else {}
 		}
 		if !is_valid_end_of_noreturn_fn {
-			c.error('@[noreturn] functions should end with a call to another @[noreturn] function, or with an infinite `for {}` loop',
-				last_stmt.pos)
-			return
+			pos = last_stmt.pos
 		}
 	}
+	if !is_valid_end_of_noreturn_fn {
+		c.error('@[noreturn] functions should end with a call to another @[noreturn] function, or with an infinite `for {}` loop',
+			pos)
+	}
 }
 
 fn uses_return_stmt(stmts []ast.Stmt) bool {

vlib/v/checker/tests/empty_fn_noreturn_err.out

@@ -0,0 +1,5 @@
+vlib/v/checker/tests/empty_fn_noreturn_err.vv:2:1: error: @[noreturn] functions should end with a call to another @[noreturn] function, or with an infinite `for {}` loop
+    1 | @[noreturn]
+    2 | fn f() {
+      | ~~~~~~
+    3 | }

vlib/v/checker/tests/empty_fn_noreturn_err.vv

@@ -0,0 +1,3 @@
+@[noreturn]
+fn f() {
+}

vlib/v/tests/reflection_test.v

@@ -21,6 +21,7 @@ fn test2(arg []string) {}
 
 @[noreturn]
 fn test3(a reflection.Function) {
+	panic('foo')
 }
 
 fn test_module_existing() {