1 files changed, 24 insertions, 3 deletions
diff --git a/source/cepis/exception.d b/source/cepis/exception.d
index 9b77449..d34f725 100644
--- a/source/cepis/exception.d
+++ b/source/cepis/exception.d
@@ -26,6 +26,8 @@ module cepis.exception;
 import core.time : Duration;
 import std.typecons : Nullable;
 
+import cepis.model : Faixa;
+
 @safe:
 
 /**
@@ -74,17 +76,36 @@ class InvalidCepException : CepisException
     }
 }
 
-/// The CEP is well-formed but does not exist in the DNE database.
+/**
+ * The CEP is well-formed but does not exist in the DNE database.
+ *
+ * When the API can say which municipality the number $(I would) have belonged
+ * to, that arrives in $(D faixa) and the message names it. It is $(B context
+ * for the error), not a result: the CEP still does not exist.
+ */
 class CepNotFoundException : CepisException
 {
     /// The CEP that was looked up, unmasked.
     const string cep;
 
+    /**
+     * The municipality whose range the CEP falls in, or null.
+     *
+     * Null whenever the API sent no usable `faixa` — including the ordinary
+     * case of a CEP in a band no municipality owns, where the API $(B omits)
+     * the field rather than sending null. Either way the lookup is still a
+     * not-found; see $(D Faixa) before showing any of it to a user.
+     */
+    const Nullable!Faixa faixa;
+
     ///
-    this(string cep, string file = __FILE__, size_t line = __LINE__) pure nothrow
+    this(string cep, Nullable!Faixa faixa = Nullable!Faixa.init,
+            string file = __FILE__, size_t line = __LINE__) pure nothrow
     {
-        super("CEP " ~ cep ~ " does not exist in the DNE database", file, line);
+        super("CEP " ~ cep ~ " does not exist in the DNE database" ~ (faixa.isNull
+                ? "" : " (that range belongs to " ~ faixa.get.localidadeUf ~ ")"), file, line);
         this.cep = cep;
+        this.faixa = faixa;
     }
 }