checker: check array builtin method call immutable errors

vlib/v/checker/fn.v

@@ -3301,6 +3301,7 @@ fn (mut c Checker) array_builtin_method_call(mut node ast.CallExpr, left_type as
 				return ast.void_type
 			}
 		}
+		c.check_for_mut_receiver(mut node.left)
 		info := left_sym.info as ast.Array
 		mut arg_expr := if method_name == 'insert' {
 			node.args[1].expr
@@ -3362,6 +3363,7 @@ fn (mut c Checker) array_builtin_method_call(mut node ast.CallExpr, left_type as
 				}
 			}
 			if method_name == 'sort_with_compare' {
+				c.check_for_mut_receiver(mut node.left)
 				node.return_type = ast.void_type
 				node.receiver_type = node.left_type.ref()
 			} else {
@@ -3773,6 +3775,7 @@ fn (mut c Checker) fixed_array_builtin_method_call(mut node ast.CallExpr, left_t
 				c.check_expr_option_or_result_call(arg.expr, c.expr(mut arg.expr))
 			}
 			if method_name == 'sort_with_compare' {
+				c.check_for_mut_receiver(mut node.left)
 				node.return_type = ast.void_type
 				node.receiver_type = node.left_type.ref()
 			} else {
@@ -3787,6 +3790,7 @@ fn (mut c Checker) fixed_array_builtin_method_call(mut node ast.CallExpr, left_t
 			if method_name == 'reverse' {
 				node.return_type = node.left_type
 			} else {
+				c.check_for_mut_receiver(mut node.left)
 				node.return_type = ast.void_type
 			}
 		}

vlib/v/checker/tests/array_method_call_immutable_err.out

@@ -0,0 +1,55 @@
+vlib/v/checker/tests/array_method_call_immutable_err.vv:7:2: error: `a2` is immutable, declare it with `mut` to make it mutable
+    5 |     a3 := ['aa', 'bb']
+    6 | 
+    7 |     a2.prepend(a1)
+      |     ~~
+    8 |     a1.insert(0, a0)
+    9 |     a3.sort_with_compare(fn (a &string, b &string) int {
+vlib/v/checker/tests/array_method_call_immutable_err.vv:8:2: error: `a1` is immutable, declare it with `mut` to make it mutable
+    6 | 
+    7 |     a2.prepend(a1)
+    8 |     a1.insert(0, a0)
+      |     ~~
+    9 |     a3.sort_with_compare(fn (a &string, b &string) int {
+   10 |         if a < b {
+vlib/v/checker/tests/array_method_call_immutable_err.vv:9:2: error: `a3` is immutable, declare it with `mut` to make it mutable
+    7 |     a2.prepend(a1)
+    8 |     a1.insert(0, a0)
+    9 |     a3.sort_with_compare(fn (a &string, b &string) int {
+      |     ~~
+   10 |         if a < b {
+   11 |             return -1
+vlib/v/checker/tests/array_method_call_immutable_err.vv:18:2: error: `a3` is immutable, declare it with `mut` to make it mutable
+   16 |         return 0
+   17 |     })
+   18 |     a3.delete(0)
+      |     ~~
+   19 |     a2.pop()
+   20 |     a3.sort()
+vlib/v/checker/tests/array_method_call_immutable_err.vv:19:2: error: `a2` is immutable, declare it with `mut` to make it mutable
+   17 |     })
+   18 |     a3.delete(0)
+   19 |     a2.pop()
+      |     ~~
+   20 |     a3.sort()
+   21 |
+vlib/v/checker/tests/array_method_call_immutable_err.vv:20:2: error: `a3` is immutable, declare it with `mut` to make it mutable
+   18 |     a3.delete(0)
+   19 |     a2.pop()
+   20 |     a3.sort()
+      |     ~~
+   21 | 
+   22 |     b0 := ['aa', 'bb']!
+vlib/v/checker/tests/array_method_call_immutable_err.vv:23:2: error: `b0` is immutable, declare it with `mut` to make it mutable
+   21 | 
+   22 |     b0 := ['aa', 'bb']!
+   23 |     b0.sort_with_compare(fn (a &string, b &string) int {
+      |     ~~
+   24 |         if a < b {
+   25 |             return -1
+vlib/v/checker/tests/array_method_call_immutable_err.vv:32:2: error: `b0` is immutable, declare it with `mut` to make it mutable
+   30 |         return 0
+   31 |     })
+   32 |     b0.sort()
+      |     ~~
+   33 | }

vlib/v/checker/tests/array_method_call_immutable_err.vv

@@ -0,0 +1,33 @@
+fn main() {
+	a0 := [1, 2]
+	a1 := [3, 4]
+	a2 := [5, 6]
+	a3 := ['aa', 'bb']
+
+	a2.prepend(a1)
+	a1.insert(0, a0)
+	a3.sort_with_compare(fn (a &string, b &string) int {
+		if a < b {
+			return -1
+		}
+		if a > b {
+			return 1
+		}
+		return 0
+	})
+	a3.delete(0)
+	a2.pop()
+	a3.sort()
+
+	b0 := ['aa', 'bb']!
+	b0.sort_with_compare(fn (a &string, b &string) int {
+		if a < b {
+			return -1
+		}
+		if a > b {
+			return 1
+		}
+		return 0
+	})
+	b0.sort()
+}