test: add tests for disallowing map/array get element/key address (#6568)

vlib/builtin/map_test.v

@@ -182,17 +182,6 @@ fn test_delete() {
 	println('two' in m) // => true, on Linux  and Windows  <-- wrong !
 }
 
-/*
-fn test_ref() {
-	m := { 'one': 1 }
-	// TODO "cannot take the address of m['one']"
-	mut one := &m['one']
-	one++
-	println(*one)
-
-}
-*/
-
 fn test_delete_size() {
     arr := ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9']
     mut m := map[string]int

vlib/v/ast/ast.v

@@ -471,7 +471,7 @@ pub struct IndexExpr {
 pub:
 	pos       token.Position
 	left      Expr
-	index     Expr // [0] or RangeExpr [start..end]
+	index     Expr // [0], RangeExpr [start..end] or map[key]
 pub mut:
 	left_type table.Type // array, map, fixed array
 	is_setter bool

vlib/v/checker/checker.v

@@ -123,15 +123,13 @@ pub fn (mut c Checker) check_files(ast_files []ast.File) {
 	mut has_main_fn := false
 	mut files_from_main_module := []&ast.File{}
 	for i in 0 .. ast_files.len {
-		unsafe {
-			file := &ast_files[i]
-			c.check(file)
-			if file.mod.name == 'main' {
-				files_from_main_module << file
-				has_main_mod_file = true
-				if c.check_file_in_main(file) {
-					has_main_fn = true
-				}
+		file := unsafe {&ast_files[i]}
+		c.check(file)
+		if file.mod.name == 'main' {
+			files_from_main_module << file
+			has_main_mod_file = true
+			if c.check_file_in_main(file) {
+				has_main_fn = true
 			}
 		}
 	}

vlib/v/checker/tests/array_get_element_address_err.out

@@ -0,0 +1,7 @@
+vlib/v/checker/tests/array_get_element_address_err.vv:3:20: error: cannot get address of array elements outside unsafe blocks
+    1 | fn main() {
+    2 |     arr_int := [int(23), 45, 7, 8]
+    3 |     ele := &arr_int[1]
+      |                    ~~~
+    4 |     println(ele)
+    5 | }

vlib/v/checker/tests/array_get_element_address_err.vv

@@ -0,0 +1,5 @@
+fn main() {
+    arr_int := [int(23), 45, 7, 8]
+    ele := &arr_int[1]
+    println(ele)
+}

vlib/v/checker/tests/map_get_value_address_err.out

@@ -0,0 +1,14 @@
+vlib/v/checker/tests/map_get_value_address_err.vv:3:12: error: cannot get address of map values outside unsafe blocks
+    1 | fn main() {
+    2 |     m := {'key' : 3}
+    3 |     a := &m['key']
+      |            ~~~~~~~
+    4 |     b := &{'foo': 4}['foo']
+    5 |     println(a)
+vlib/v/checker/tests/map_get_value_address_err.vv:4:21: error: cannot get address of map values outside unsafe blocks
+    2 |     m := {'key' : 3}
+    3 |     a := &m['key']
+    4 |     b := &{'foo': 4}['foo']
+      |                     ~~~~~~~
+    5 |     println(a)
+    6 |     println(b)

vlib/v/checker/tests/map_get_value_address_err.vv

@@ -0,0 +1,7 @@
+fn main() {
+    m := {'key' : 3}
+    a := &m['key']
+    b := &{'foo': 4}['foo']
+    println(a)
+    println(b)
+}

vlib/v/tests/unsafe_test.v

@@ -30,18 +30,13 @@ fn (s S1) f() {
 
 fn test_funcs() {
 	s := S1{}
-	unsafe {
-		s.f()
-	}
+	unsafe {s.f()}
 	_ = C.strerror(0) // [trusted] function prototype in builtin/cfns.c.v
 }
 
 fn test_if_expr_unsafe() {
 	i := 4
-	p := if true {
-		unsafe {&i}
-	}
-	else {unsafe {&i}}
+	p := if true { unsafe {&i} } else { unsafe {&i} }
 	assert *p == 4
 }
 
@@ -54,3 +49,14 @@ fn test_unsafe_if_stmt() int {
 	}
 	return i
 }
+
+fn test_map_address_index() {
+	m := {
+		'one': 1
+	}
+	unsafe {
+		mut one := &m['one']
+		one++
+		println(*one)
+	}
+}