fixes #19986; mutable view from immutable location (#20134)

* fixes #19986; mutable view from immutable location

* fixes the tests

tests/views/t19986.nim

@@ -0,0 +1,42 @@
+discard """
+  cmd: '''nim check --hints:off $file'''
+  action: reject
+nimout: '''
+t19986.nim(19, 7) Error: 'foo' borrows from the immutable location 'a' and attempts to mutate it
+t19986.nim(28, 7) Error: 'foo' borrows from the immutable location 'a' and attempts to mutate it
+t19986.nim(37, 7) Error: 'foo' borrows from the immutable location 'a' and attempts to mutate it
+'''
+"""
+
+{.experimental: "views".}
+
+type
+  Object = object
+    id: int
+
+proc foo() =
+  let a = Object(id: 3)
+  var foo: var Object = a
+
+  foo.id = 777
+  echo a
+
+foo()
+
+proc bar() =
+  let a = "123"
+  var foo: var string = a
+
+  foo[0] = '7'
+  echo a
+
+bar()
+
+proc main() =
+  let a = 3
+  var foo: var int = a
+
+  foo = 777
+  echo a
+
+main()