From 5ac1e14e7f6d103dbef9cd480492aa19bea49ab0 Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Mon, 21 Apr 2025 12:51:15 -0300
Subject: [PATCH] checker: add a deprecation note for `any` arg, prevent `any`
 from being used as map key,value or array type (#24277)

---
 vlib/v/checker/containers.v            |  8 +++++-
 vlib/v/checker/fn.v                    |  5 ++++
 vlib/v/checker/tests/deprecate_any.out | 38 ++++++++++++++++++++++++++
 vlib/v/checker/tests/deprecate_any.vv  |  7 +++++
 4 files changed, 57 insertions(+), 1 deletion(-)
 create mode 100644 vlib/v/checker/tests/deprecate_any.out
 create mode 100644 vlib/v/checker/tests/deprecate_any.vv

diff --git a/vlib/v/checker/containers.v b/vlib/v/checker/containers.v
index c751f26a21..45c8fe1e3c 100644
--- a/vlib/v/checker/containers.v
+++ b/vlib/v/checker/containers.v
@@ -18,7 +18,7 @@ fn (mut c Checker) array_init(mut node ast.ArrayInit) ast.Type {
 		}
 		if node.elem_type != 0 {
 			elem_sym := c.table.sym(node.elem_type)
-
+			c.check_any_type(node.elem_type, elem_sym, node.pos)
 			if node.typ.has_flag(.option) && (node.has_cap || node.has_len) {
 				c.error('Option array `${elem_sym.name}` cannot have initializers', node.pos)
 			}
@@ -531,6 +531,12 @@ fn (mut c Checker) map_init(mut node ast.MapInit) ast.Type {
 		c.ensure_type_exists(info.value_type, node.pos)
 		node.key_type = info.key_type
 		node.value_type = info.value_type
+		if (c.table.sym(info.key_type).language == .v && info.key_type == ast.any_type)
+			|| (c.table.sym(info.value_type).language == .v && info.value_type == ast.any_type) {
+			c.note('the `any` type is deprecated and will be removed soon - either use an empty interface, or a sum type',
+				node.pos)
+			c.error('cannot use type `any` here', node.pos)
+		}
 		return node.typ
 	}
 
diff --git a/vlib/v/checker/fn.v b/vlib/v/checker/fn.v
index d1c887351a..c79256cb27 100644
--- a/vlib/v/checker/fn.v
+++ b/vlib/v/checker/fn.v
@@ -280,6 +280,11 @@ fn (mut c Checker) fn_decl(mut node ast.FnDecl) {
 				c.error('result type arguments are not supported', param.type_pos)
 			}
 			arg_typ_sym := c.table.sym(param.typ)
+			if arg_typ_sym.language == .v && param.typ == ast.any_type
+				&& c.file.mod.name != 'builtin' {
+				c.note('the `any` type is deprecated and will be removed soon - either use an empty interface, or a sum type',
+					param.pos)
+			}
 			// resolve unresolved fixed array size e.g. [mod.const]array_type
 			if arg_typ_sym.info is ast.ArrayFixed
 				&& c.array_fixed_has_unresolved_size(arg_typ_sym.info) {
diff --git a/vlib/v/checker/tests/deprecate_any.out b/vlib/v/checker/tests/deprecate_any.out
new file mode 100644
index 0000000000..cac80b2ee9
--- /dev/null
+++ b/vlib/v/checker/tests/deprecate_any.out
@@ -0,0 +1,38 @@
+vlib/v/checker/tests/deprecate_any.vv:1:8: notice: the `any` type is deprecated and will be removed soon - either use an empty interface, or a sum type
+    1 | fn foo(a any) {}
+      |        ^
+    2 | 
+    3 | fn main() {
+vlib/v/checker/tests/deprecate_any.vv:5:7: notice: the `any` type is deprecated and will be removed soon - either use an empty interface, or a sum type
+    3 | fn main() {
+    4 |     _ := []any{}
+    5 |     _ := map[int]any{}
+      |          ~~~~~~~~~~~~~
+    6 |     _ := map[any]int{}
+    7 | }
+vlib/v/checker/tests/deprecate_any.vv:6:7: notice: the `any` type is deprecated and will be removed soon - either use an empty interface, or a sum type
+    4 |     _ := []any{}
+    5 |     _ := map[int]any{}
+    6 |     _ := map[any]int{}
+      |          ~~~~~~~~~~~~~
+    7 | }
+vlib/v/checker/tests/deprecate_any.vv:4:7: error: cannot use type `any` here
+    2 | 
+    3 | fn main() {
+    4 |     _ := []any{}
+      |          ~~~~~~
+    5 |     _ := map[int]any{}
+    6 |     _ := map[any]int{}
+vlib/v/checker/tests/deprecate_any.vv:5:7: error: cannot use type `any` here
+    3 | fn main() {
+    4 |     _ := []any{}
+    5 |     _ := map[int]any{}
+      |          ~~~~~~~~~~~~~
+    6 |     _ := map[any]int{}
+    7 | }
+vlib/v/checker/tests/deprecate_any.vv:6:7: error: cannot use type `any` here
+    4 |     _ := []any{}
+    5 |     _ := map[int]any{}
+    6 |     _ := map[any]int{}
+      |          ~~~~~~~~~~~~~
+    7 | }
diff --git a/vlib/v/checker/tests/deprecate_any.vv b/vlib/v/checker/tests/deprecate_any.vv
new file mode 100644
index 0000000000..cbe6d39a88
--- /dev/null
+++ b/vlib/v/checker/tests/deprecate_any.vv
@@ -0,0 +1,7 @@
+fn foo(a any) {}
+
+fn main() {
+	_ := []any{}
+	_ := map[int]any{}
+	_ := map[any]int{}
+}