[#952] Fix false positive type warning with into and transducer

clj-kondo · Aug 31, 2020 · bb12c68 · bb12c68
1 parent 2871523
commit bb12c68
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Showing 2 changed files with 13 additions and 1 deletion.
diff --git a/src/clj_kondo/impl/types.clj b/src/clj_kondo/impl/types.clj
@@ -35,7 +35,7 @@
    :keyword #{:ifn}
    :symbol #{:ifn}
    :associative #{:seqable :coll :ifn}
-   :transducer #{:ifn}
+   :transducer #{:ifn :fn}
    :list #{:seq :sequential :seqable :coll :stack}
    :seq #{:seqable :sequential :coll}
    :sequential #{:coll :seqable}})
@@ -51,6 +51,7 @@
    :associative #{:map :vector :sequential :stack}
    :ifn #{:fn :transducer :symbol :keyword :map :set :vector :associative :seqable :coll
           :sequential :stack}
+   :fn #{:transducer}
    :nat-int #{:pos-int}
    :seq #{:list :stack}
    :stack #{:list :vector :seq :sequential :seqable :coll :ifn :associative}

diff --git a/test/clj_kondo/types_test.clj b/test/clj_kondo/types_test.clj
@@ -646,6 +646,17 @@
   (is (empty? (lint! "
 (require 'clojure.string)
 (clojure.string/replace \"hallo\" \"a\" (first [\"e\"]))
+" {:linters {:type-mismatch {:level :error}}})))
+  (is (empty? (lint! "
+(defn transducer []
+  (fn [rf]
+    (fn
+      ([] (rf))
+      ([result] (rf result))
+      ([result input]
+       (rf result input)))))
+
+(into [] (transducer) [1 2 3])
 " {:linters {:type-mismatch {:level :error}}}))))
 
 (deftest binding-call-test