aliases: Normalize right-hand side addresses

The right-hand side addresses of an alias should be normalized, to
maintain the internal invariant that we always deal with normalized
addresses.

Otherwise, strange situations may arise, such as the same domain having
two different domaininfo structures depending on case.

internal/aliases/aliases.go

@@ -299,6 +299,7 @@ func parseFile(domain, path string) (map[string][]Recipient, error) {
 				if !strings.Contains(a, "@") {
 					a = a + "@" + domain
 				}
+				a, _ = normalize.Addr(a)
 				rs = append(rs, Recipient{a, EMAIL})
 			}
 			aliases[addr] = rs

internal/aliases/aliases_test.go

@@ -237,6 +237,9 @@ a@dom: x@dom
 o1: a
 o1: b
 
+# Check that we normalize the right hand side.
+aA: bB@dom-B
+
 # Finally one to make the file NOT end in \n:
 y: z`
 
@@ -255,6 +258,8 @@ func TestRichFile(t *testing.T) {
 		{"c@dom", []Recipient{{"d@e", EMAIL}, {"f@dom", EMAIL}}},
 		{"x@dom", []Recipient{{"command", PIPE}}},
 		{"o1@dom", []Recipient{{"b@dom", EMAIL}}},
+		{"aA@dom", []Recipient{{"bb@dom-b", EMAIL}}},
+		{"aa@dom", []Recipient{{"bb@dom-b", EMAIL}}},
 		{"y@dom", []Recipient{{"z@dom", EMAIL}}},
 	}
 	cases.check(t, resolver)