diff --git a/main.v b/main.v
new file mode 100644
index 0000000000..a6ecd7a2ba
--- /dev/null
+++ b/main.v
@@ -0,0 +1,7 @@
+fn main() {
+	list := [1,2,3].filter(stringsss(it))
+}
+
+fn stringsss(arg int) string {
+	return ''
+}
\ No newline at end of file
diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index eb42ffd7c3..31f06d7067 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -1409,6 +1409,13 @@ fn (mut c Checker) check_map_and_filter(is_map bool, elem_typ ast.Type, call_exp
 				}
 			}
 		}
+		ast.CallExpr {
+			if is_map && arg_expr.return_type == table.void_type {
+				c.error('type mismatch, `$arg_expr.name` does not return anything', arg_expr.pos)
+			} else if !is_map && arg_expr.return_type != table.bool_type {
+				c.error('type mismatch, `$arg_expr.name` must return a bool', arg_expr.pos)
+			}
+		}
 		else {}
 	}
 }
diff --git a/vlib/v/checker/tests/filter_func_return_nonbool_err.out b/vlib/v/checker/tests/filter_func_return_nonbool_err.out
new file mode 100644
index 0000000000..e62f5db75f
--- /dev/null
+++ b/vlib/v/checker/tests/filter_func_return_nonbool_err.out
@@ -0,0 +1,6 @@
+vlib/v/checker/tests/filter_func_return_nonbool_err.vv:2:25: error: type mismatch, `stringsss` must return a bool
+    1 | fn main() {
+    2 |     list := [1,2,3].filter(stringsss(it))
+      |                            ~~~~~~~~~~~~~
+    3 | }
+    4 |
diff --git a/vlib/v/checker/tests/filter_func_return_nonbool_err.vv b/vlib/v/checker/tests/filter_func_return_nonbool_err.vv
new file mode 100644
index 0000000000..a6ecd7a2ba
--- /dev/null
+++ b/vlib/v/checker/tests/filter_func_return_nonbool_err.vv
@@ -0,0 +1,7 @@
+fn main() {
+	list := [1,2,3].filter(stringsss(it))
+}
+
+fn stringsss(arg int) string {
+	return ''
+}
\ No newline at end of file
diff --git a/vlib/v/checker/tests/map_func_void_return_err.out b/vlib/v/checker/tests/map_func_void_return_err.out
new file mode 100644
index 0000000000..943e7b153e
--- /dev/null
+++ b/vlib/v/checker/tests/map_func_void_return_err.out
@@ -0,0 +1,6 @@
+vlib/v/checker/tests/map_func_void_return_err.vv:2:22: error: type mismatch, `voids` does not return anything
+    1 | fn main() {
+    2 |     list := [1,2,3].map(voids(it))
+      |                         ~~~~~~~~~
+    3 | }
+    4 |
diff --git a/vlib/v/checker/tests/map_func_void_return_err.vv b/vlib/v/checker/tests/map_func_void_return_err.vv
new file mode 100644
index 0000000000..bd5446e128
--- /dev/null
+++ b/vlib/v/checker/tests/map_func_void_return_err.vv
@@ -0,0 +1,7 @@
+fn main() {
+	list := [1,2,3].map(voids(it))
+}
+
+fn voids(arg int) {
+	println(arg)
+}