CLJS-3000: Don't pass meta to next/rest/empty of seqs

* Fix metadata on ChunkedCons, ValSeq and PersistentTreeMapSeq.
* Remove multiples useless calls to with-meta when constructing EmptyLists
  introduced in CLJS-1888

Author: thomasmulvaney

src/main/cljs/cljs/core.cljs

@@ -3590,15 +3590,15 @@ reduces them without incurring seq initialization"
   (-first [coll] (-nth chunk 0))
   (-rest [coll]
     (if (> (-count chunk) 1)
-      (ChunkedCons. (-drop-first chunk) more meta nil)
+      (ChunkedCons. (-drop-first chunk) more nil nil)
       (if (nil? more)
         ()
         more)))
 
   INext
   (-next [coll]
     (if (> (-count chunk) 1)
-      (ChunkedCons. (-drop-first chunk) more meta nil)
+      (ChunkedCons. (-drop-first chunk) more nil nil)
       (when-not (nil? more)
         (-seq more))))
 
@@ -3620,7 +3620,7 @@ reduces them without incurring seq initialization"
     (cons o this))
 
   IEmptyableCollection
-  (-empty [coll] (-with-meta (.-EMPTY List) meta))
+  (-empty [coll] (.-EMPTY List))
 
   IHash
   (-hash [coll] (caching-hash coll hash-ordered-coll __hash)))
@@ -8210,7 +8210,7 @@ reduces them without incurring seq initialization"
   (-conj [coll o] (cons o coll))
 
   IEmptyableCollection
-  (-empty [coll] (-with-meta (.-EMPTY List) meta))
+  (-empty [coll] (.-EMPTY List))
 
   IHash
   (-hash [coll] (caching-hash coll hash-ordered-coll __hash))
@@ -9051,7 +9051,7 @@ reduces them without incurring seq initialization"
     (cons o coll))
 
   IEmptyableCollection
-  (-empty [coll] (-with-meta (.-EMPTY List) _meta))
+  (-empty [coll] (.-EMPTY List))
 
   IHash
   (-hash [coll] (hash-ordered-coll coll))
@@ -9066,7 +9066,7 @@ reduces them without incurring seq initialization"
                  (-next mseq)
                  (next mseq))]
       (if-not (nil? nseq)
-        (ValSeq. nseq _meta)
+        (ValSeq. nseq nil)
         ())))
 
   INext
@@ -9075,7 +9075,7 @@ reduces them without incurring seq initialization"
                  (-next mseq)
                  (next mseq))]
       (when-not (nil? nseq)
-        (ValSeq. nseq _meta))))
+        (ValSeq. nseq nil))))
 
   IReduce
   (-reduce [coll f] (seq-reduce f coll))
@@ -9746,7 +9746,7 @@ reduces them without incurring seq initialization"
   (-conj [rng o] (cons o rng))
 
   IEmptyableCollection
-  (-empty [rng] (-with-meta (.-EMPTY List) nil))
+  (-empty [rng] (.-EMPTY List))
 
   ISequential
   IEquiv

src/test/cljs/cljs/metadata_test.cljc

@@ -129,13 +129,24 @@
       (testing "Medium"
         (seq-interface-tests (seq (hash-map 0 1 2 3 4 5))))
       (testing "Large"
-        (seq-interface-tests (seq (apply hash-map (range 100))))))
+        (seq-interface-tests (seq (apply hash-map (range 100)))))
+      (testing "KeySeq"
+        (seq-interface-tests (keys (apply hash-map (range 10)))))
+      (testing "ValSeq"
+        (seq-interface-tests (vals (apply hash-map (range 10))))))
 
     (testing "PersistentArrayMap"
       (testing "Empty"
         (seq-interface-tests (seq (array-map))))
       (testing "Medium"
-        (seq-interface-tests (seq (array-map 0 1 2 3 4 5))))))
+        (seq-interface-tests (seq (array-map 0 1 2 3 4 5))))
+      (testing "KeySeq"
+        (seq-interface-tests (keys (apply array-map (range 10)))))
+      (testing "ValSeq"
+        (seq-interface-tests (vals (apply array-map (range 10))))))
+
+    (testing "PersistentTreeMap"
+      (seq-interface-tests (seq (sorted-map :a 1 :b 2 :c 3)))))
 
   (testing "generators"
     (testing "cycle"
@@ -145,4 +156,8 @@
     (testing "repeat"
       (seq-interface-tests (repeat 10 :x)))
     (testing "iterate"
-      (seq-interface-tests (iterate inc 0)))))
+      (seq-interface-tests (iterate inc 0))))
+
+  (testing "ChunkedCons"
+    (let [chunked-cons (seq (map inc (vec (range 100))))]
+      (seq-interface-tests chunked-cons))))