From e51f0be6db5807b4e4ea03634d05c824c3fb7ab5 Mon Sep 17 00:00:00 2001
From: yuyi <yuyi98@163.com>
Date: Tue, 13 Sep 2022 15:04:21 +0800
Subject: [PATCH] checker: check taking the address of map field outside unsafe
 block (#15737)

---
 vlib/toml/parser/parser.v                     |  4 ++-
 vlib/v/checker/checker.v                      |  6 +++++
 .../tests/struct_field_map_address_err.out    |  7 +++++
 .../tests/struct_field_map_address_err.vv     | 27 +++++++++++++++++++
 4 files changed, 43 insertions(+), 1 deletion(-)
 create mode 100644 vlib/v/checker/tests/struct_field_map_address_err.out
 create mode 100644 vlib/v/checker/tests/struct_field_map_address_err.vv

diff --git a/vlib/toml/parser/parser.v b/vlib/toml/parser/parser.v
index 38c95f9b3d..8bd8f0af8b 100644
--- a/vlib/toml/parser/parser.v
+++ b/vlib/toml/parser/parser.v
@@ -561,7 +561,9 @@ pub fn (mut p Parser) root_table() ? {
 
 				if p.tok.kind == .lsbr {
 					// Parse `[[table]]`
-					p.array_of_tables(mut &p.root_map)?
+					unsafe {
+						p.array_of_tables(mut &p.root_map)?
+					}
 					p.skip_next = true // skip calling p.next() in coming iteration
 					util.printdbg(@MOD + '.' + @STRUCT + '.' + @FN, 'leaving double bracket at "$p.tok.kind" "$p.tok.lit". NEXT is "$p.peek_tok.kind "$p.peek_tok.lit"')
 				} else if peek_tok.kind == .period {
diff --git a/vlib/v/checker/checker.v b/vlib/v/checker/checker.v
index 4ecf8388c1..6acd3fb63f 100644
--- a/vlib/v/checker/checker.v
+++ b/vlib/v/checker/checker.v
@@ -3328,6 +3328,12 @@ pub fn (mut c Checker) prefix_expr(mut node ast.PrefixExpr) ast.Type {
 				c.warn('cannot take an address of const outside `unsafe`', node.right.pos)
 			}
 		}
+		if node.right is ast.SelectorExpr {
+			typ_sym := c.table.sym(right_type)
+			if typ_sym.kind == .map && !c.inside_unsafe {
+				c.error('cannot take the address of map values outside `unsafe`', node.pos)
+			}
+		}
 		if mut node.right is ast.IndexExpr {
 			typ_sym := c.table.sym(node.right.left_type)
 			mut is_mut := false
diff --git a/vlib/v/checker/tests/struct_field_map_address_err.out b/vlib/v/checker/tests/struct_field_map_address_err.out
new file mode 100644
index 0000000000..44047f2119
--- /dev/null
+++ b/vlib/v/checker/tests/struct_field_map_address_err.out
@@ -0,0 +1,7 @@
+vlib/v/checker/tests/struct_field_map_address_err.vv:12:26: error: cannot take the address of map values outside `unsafe`
+   10 |     mut s := &StructWithMap{}
+   11 |     s.m['abc'] = StructWithMap{'abc', {}}
+   12 |     pointer_to_map_value := &s.m['abc'].m['xyz'].m
+      |                             ^
+   13 |     dump(ptr_str(pointer_to_map_value))
+   14 |     return s, pointer_to_map_value
diff --git a/vlib/v/checker/tests/struct_field_map_address_err.vv b/vlib/v/checker/tests/struct_field_map_address_err.vv
new file mode 100644
index 0000000000..7756931539
--- /dev/null
+++ b/vlib/v/checker/tests/struct_field_map_address_err.vv
@@ -0,0 +1,27 @@
+import os
+
+struct StructWithMap {
+mut:
+	name string
+	m    map[string]StructWithMap
+}
+
+fn abc() (&StructWithMap, &map[string]StructWithMap) {
+	mut s := &StructWithMap{}
+	s.m['abc'] = StructWithMap{'abc', {}}
+	pointer_to_map_value := &s.m['abc'].m['xyz'].m
+	dump(ptr_str(pointer_to_map_value))
+	return s, pointer_to_map_value
+}
+
+fn main() {
+	mut s, p := abc()
+	n := os.args[1] or { '2' }.int()
+	dump(n)
+	for i in 0 .. n {
+		s.m['$i'] = StructWithMap{}
+	}
+	dump(s.m['abc'])
+	dump(p)
+	eprintln('-----------------------------------------------------')
+}