From 59eb76c81d81f1c2886b4dcac2746b5b93364d92 Mon Sep 17 00:00:00 2001
From: Felipe Pena <felipensp@gmail.com>
Date: Sun, 9 Jul 2023 09:41:24 -0300
Subject: [PATCH] v: allow `none` for not first values on map initialization
 (#18821)

---
 vlib/v/checker/containers.v                |  8 +++++
 vlib/v/checker/tests/map_with_none_err.out | 34 ++++++++++++++++++++++
 vlib/v/checker/tests/map_with_none_err.vv  | 15 ++++++++++
 vlib/v/gen/c/cgen.v                        |  2 +-
 vlib/v/tests/option_map_none_test.v        | 17 +++++++++++
 5 files changed, 75 insertions(+), 1 deletion(-)
 create mode 100644 vlib/v/checker/tests/map_with_none_err.out
 create mode 100644 vlib/v/checker/tests/map_with_none_err.vv
 create mode 100644 vlib/v/tests/option_map_none_test.v

diff --git a/vlib/v/checker/containers.v b/vlib/v/checker/containers.v
index d8ca0f2242..b87913b7cd 100644
--- a/vlib/v/checker/containers.v
+++ b/vlib/v/checker/containers.v
@@ -409,6 +409,11 @@ fn (mut c Checker) map_init(mut node ast.MapInit) ast.Type {
 		expecting_interface_map := map_value_sym.kind == .interface_
 		//
 		mut same_key_type := true
+
+		if node.keys.len == 1 && val0_type == ast.none_type {
+			c.error('map value cannot be only `none`', node.vals[0].pos())
+		}
+
 		for i, mut key in node.keys {
 			if i == 0 && !use_expected_type {
 				continue
@@ -445,6 +450,9 @@ fn (mut c Checker) map_init(mut node ast.MapInit) ast.Type {
 					c.error('invalid map value: ${msg}', val.pos())
 				}
 			}
+			if val_type == ast.none_type && val0_type.has_flag(.option) {
+				continue
+			}
 			if !c.check_types(val_type, val0_type)
 				|| val0_type.has_flag(.option) != val_type.has_flag(.option)
 				|| (i == 0 && val_type.is_number() && val0_type.is_number()
diff --git a/vlib/v/checker/tests/map_with_none_err.out b/vlib/v/checker/tests/map_with_none_err.out
new file mode 100644
index 0000000000..6fc728e4b0
--- /dev/null
+++ b/vlib/v/checker/tests/map_with_none_err.out
@@ -0,0 +1,34 @@
+vlib/v/checker/tests/map_with_none_err.vv:2:6: warning: unused variable: `a`
+    1 | fn main() {
+    2 |     mut a := {
+      |         ^
+    3 |         'bar': none
+    4 |     }
+vlib/v/checker/tests/map_with_none_err.vv:6:6: warning: unused variable: `b`
+    4 |     }
+    5 | 
+    6 |     mut b := {
+      |         ^
+    7 |         'foo': 1,
+    8 |         'bar': none
+vlib/v/checker/tests/map_with_none_err.vv:11:6: warning: unused variable: `c`
+    9 |     }
+   10 | 
+   11 |     mut c := {
+      |         ^
+   12 |         'foo': ?int(none),
+   13 |         'bar': none
+vlib/v/checker/tests/map_with_none_err.vv:3:10: error: map value cannot be only `none`
+    1 | fn main() {
+    2 |     mut a := {
+    3 |         'bar': none
+      |                ~~~~
+    4 |     }
+    5 |
+vlib/v/checker/tests/map_with_none_err.vv:8:10: error: invalid map value: expected `int`, not `none`
+    6 |     mut b := {
+    7 |         'foo': 1,
+    8 |         'bar': none
+      |                ~~~~
+    9 |     }
+   10 |
diff --git a/vlib/v/checker/tests/map_with_none_err.vv b/vlib/v/checker/tests/map_with_none_err.vv
new file mode 100644
index 0000000000..bda994999b
--- /dev/null
+++ b/vlib/v/checker/tests/map_with_none_err.vv
@@ -0,0 +1,15 @@
+fn main() {
+	mut a := {
+		'bar': none
+	}
+
+	mut b := {
+		'foo': 1,
+		'bar': none
+	}
+
+	mut c := {
+		'foo': ?int(none),
+		'bar': none
+	}
+}
\ No newline at end of file
diff --git a/vlib/v/gen/c/cgen.v b/vlib/v/gen/c/cgen.v
index bca703a253..5a458227f5 100644
--- a/vlib/v/gen/c/cgen.v
+++ b/vlib/v/gen/c/cgen.v
@@ -4018,7 +4018,7 @@ fn (mut g Gen) map_init(node ast.MapInit) {
 			}
 			if value_sym.kind == .sum_type {
 				g.expr_with_cast(expr, node.val_types[i], unwrap_val_typ)
-			} else if node.val_types[i].has_flag(.option) {
+			} else if node.val_types[i].has_flag(.option) || node.val_types[i] == ast.none_type {
 				g.expr_with_opt(expr, node.val_types[i], unwrap_val_typ)
 			} else {
 				g.expr(expr)
diff --git a/vlib/v/tests/option_map_none_test.v b/vlib/v/tests/option_map_none_test.v
new file mode 100644
index 0000000000..722c809205
--- /dev/null
+++ b/vlib/v/tests/option_map_none_test.v
@@ -0,0 +1,17 @@
+fn test_main() {
+	mut a := {
+		'foo': ?int(1)
+		'bar': none
+	}
+	a['foo'] = 1
+	assert dump(a) == a
+}
+
+fn test_none() {
+	mut a := {
+		'foo': ?int(1)
+		'bar': none
+	}
+	a['foo'] = none
+	assert dump(a) == a
+}