"Call to clojure.core/ns did not conform to spec"

[Hakim]

If I try to require seqexp on a clojure with alpha build including spec I get

boot.user=> (require '[net.cgrand.seqexp :as se])

clojure.lang.Compiler$CompilerException: clojure.lang.ExceptionInfo: Call to clojure.core/ns did not conform to spec:
                                         In: [3 0] val: require fails spec: :clojure.core.specs/ns-refer-clojure at: [:args :clauses :refer-clojure :clause] predicate: #{:refer-clojure}
                                         In: [3 0] val: require fails spec: :clojure.core.specs/ns-require at: [:args :clauses :require :clause] predicate: #{:require}
                                         In: [3 0] val: require fails spec: :clojure.core.specs/ns-import at: [:args :clauses :import :clause] predicate: #{:import}
                                         In: [3 0] val: require fails spec: :clojure.core.specs/ns-use at: [:args :clauses :use :clause] predicate: #{:use}
                                         In: [3 0] val: require fails spec: :clojure.core.specs/ns-refer at: [:args :clauses :refer :clause] predicate: #{:refer}
                                         In: [3 0] val: require fails spec: :clojure.core.specs/ns-load at: [:args :clauses :load :clause] predicate: #{:load}
                                         In: [3 0] val: require fails spec: :clojure.core.specs/ns-gen-class at: [:args :clauses :gen-class :clause] predicate: #{:gen-class}
                                         :clojure.spec/args  (net.cgrand.seqexp "Regular expressions for sequences." (:refer-clojure :exclude [+ * repeat +' *']) (require [clojure.walk :as walk]))
                                          #:clojure.spec{:problems ({:path [:args :clauses :refer-clojure :clause], :pred #{:refer-clojure}, :val require, :via [:clojure.core.specs/ns-refer-clojure :clojure.core.specs/ns-refer-clojure], :in [3 0]} {:path [:args :clauses :require :clause], :pred #{:require}, :val require, :via [:clojure.core.specs/ns-require :clojure.core.specs/ns-require], :in [3 0]} {:path [:args :clauses :import :clause], :pred #{:import}, :val require, :via [:clojure.core.specs/ns-import :clojure.core.specs/ns-import], :in [3 0]} {:path [:args :clauses :use :clause], :pred #{:use}, :val require, :via [:clojure.core.specs/ns-use :clojure.core.specs/ns-use], :in [3 0]} {:path [:args :clauses :refer :clause], :pred #{:refer}, :val require, :via [:clojure.core.specs/ns-refer :clojure.core.specs/ns-refer], :in [3 0]} {:path [:args :clauses :load :clause], :pred #{:load}, :val require, :via [:clojure.core.specs/ns-load :clojure.core.specs/ns-load], :in [3 0]} {:path [:args :clauses :gen-class :clause], :pred #{:gen-class}, :val require, :via [:clojure.core.specs/ns-gen-class :clojure.core.specs/ns-gen-class], :in [3 0]}), :args (net.cgrand.seqexp "Regular expressions for sequences." (:refer-clojure :exclude [+ * repeat +' *']) (require [clojure.walk :as walk]))}, compiling:(net/cgrand/seqexp.clj:1:1)
             clojure.lang.ExceptionInfo: Call to clojure.core/ns did not conform to spec:
                                         In: [3 0] val: require fails spec: :clojure.core.specs/ns-refer-clojure at: [:args :clauses :refer-clojure :clause] predicate: #{:refer-clojure}
                                         In: [3 0] val: require fails spec: :clojure.core.specs/ns-require at: [:args :clauses :require :clause] predicate: #{:require}
                                         In: [3 0] val: require fails spec: :clojure.core.specs/ns-import at: [:args :clauses :import :clause] predicate: #{:import}
                                         In: [3 0] val: require fails spec: :clojure.core.specs/ns-use at: [:args :clauses :use :clause] predicate: #{:use}
                                         In: [3 0] val: require fails spec: :clojure.core.specs/ns-refer at: [:args :clauses :refer :clause] predicate: #{:refer}
                                         In: [3 0] val: require fails spec: :clojure.core.specs/ns-load at: [:args :clauses :load :clause] predicate: #{:load}
                                         In: [3 0] val: require fails spec: :clojure.core.specs/ns-gen-class at: [:args :clauses :gen-class :clause] predicate: #{:gen-class}
                                         :clojure.spec/args  (net.cgrand.seqexp "Regular expressions for sequences." (:refer-clojure :exclude [+ * repeat +' *']) (require [clojure.walk :as walk]))

[Hakim]

Great, many thanks!