Fix apply with list args dispatching to wrong arity

knownSeqLength now handles .list (PersistentList) and .cons (cons chain)
types, enabling apply to correctly dispatch to exact arities instead of
always falling through to the variadic path.

Fixes eduction (5 transducer test failures) where (apply comp (butlast
xforms)) was calling comp's variadic arity instead of the single-arg
arity, producing a non-functional transducer wrapper.

Author: chaploud

README.md

@@ -24,7 +24,7 @@ a native implementation targeting behavioral compatibility with Clojure.
 - **Wasm FFI** — call WebAssembly modules from Clojure (523 opcodes including SIMD + GC)
 - **Dual backend** — bytecode VM (default) + TreeWalk interpreter (reference)
 - **deps.edn compatible** — Clojure CLI subset (-A/-M/-X/-P, git deps, local deps)
-- **1050+ vars** across 30+ namespaces (637/706 clojure.core)
+- **1100+ vars** across 30+ namespaces (651/706 clojure.core)
 
 ## Getting Started
 
@@ -94,7 +94,7 @@ Known divergences are documented in [DIFFERENCES.md](DIFFERENCES.md).
 
 | Namespace              | Vars   | Description                          |
 |------------------------|--------|--------------------------------------|
-| clojure.core           | 637/706| Core language functions              |
+| clojure.core           | 651/706| Core language functions              |
 | clojure.core.protocols | 10/11  | CollReduce, IKVReduce, Datafiable    |
 | clojure.core.reducers  | 22/22  | Parallel fold, monoid, reducers      |
 
@@ -107,7 +107,7 @@ Known divergences are documented in [DIFFERENCES.md](DIFFERENCES.md).
 | clojure.set        | 12/12  | Set operations                 |
 | clojure.walk       | 10/10  | Tree walking                   |
 | clojure.zip        | 28/28  | Zipper data structure          |
-| clojure.data       | 3/5    | Data diff                      |
+| clojure.data       | 5/5    | Data diff                      |
 | clojure.edn        | 2/2    | EDN reader                     |
 | clojure.template   | 2/2    | Code templates                 |
 | clojure.xml        | 7/9    | XML parsing (pure Clojure)     |
@@ -120,24 +120,25 @@ Known divergences are documented in [DIFFERENCES.md](DIFFERENCES.md).
 | Namespace              | Vars   | Description                    |
 |------------------------|--------|--------------------------------|
 | clojure.spec.alpha     | 87/87  | Spec validation, s/def, s/valid?|
-| clojure.spec.gen.alpha | 27/54  | Spec generators                |
+| clojure.spec.gen.alpha | 54/54  | Spec generators                |
+| clojure.core.specs.alpha| 1/1   | Spec for core macros           |
 
 **Dev & Test**
 
 | Namespace          | Vars   | Description                    |
 |--------------------|--------|--------------------------------|
-| clojure.test       | 32/39  | Test framework                 |
+| clojure.test       | 38/39  | Test framework                 |
 | clojure.test.tap   | 7/7    | TAP output formatter           |
 | clojure.repl       | 11/13  | doc, dir, apropos, source, pst |
-| clojure.pprint     | 9/26   | Pretty printing, print-table   |
+| clojure.pprint     | 22/26  | Pretty printing, print-table   |
 | clojure.stacktrace | 6/6    | Stack trace utilities          |
 | clojure.main       | 16/20  | REPL, script loading, ex-triage|
 
 **IO & System**
 
 | Namespace              | Vars   | Description                    |
 |------------------------|--------|--------------------------------|
-| clojure.java.io        | 7/19   | File I/O (Zig-native)         |
+| clojure.java.io        | 19/19  | File I/O (Zig-native)         |
 | clojure.java.shell     | 5/5    | Shell commands (sh)            |
 | clojure.java.browse    | 2/2    | Open URL in browser            |
 | clojure.java.process   | 5/9    | Process API (Clojure 1.12)     |
@@ -146,7 +147,7 @@ Known divergences are documented in [DIFFERENCES.md](DIFFERENCES.md).
 
 | Namespace              | Vars   | Description                    |
 |------------------------|--------|--------------------------------|
-| clojure.core.server    | 7/11   | Socket REPL, prepl (stub)      |
+| clojure.core.server    | 7/11   | Socket REPL, prepl (partial)   |
 | clojure.repl.deps      | 3/3    | Dynamic lib addition (stub)    |
 
 **ClojureWasm Extensions**

src/builtins/collections.zig

@@ -1065,7 +1065,23 @@ fn knownSeqLength(val: Value) ?usize {
         .set => val.asSet().count(),
         .string => val.asString().len,
         .nil => 0,
-        else => null, // cons, lazy_seq — can't know without realization
+        .list => val.asList().count(),
+        .cons => blk: {
+            // Walk cons chain to count (finite lists from butlast etc.)
+            var count: usize = 0;
+            var cur = val;
+            while (cur.tag() == .cons) {
+                count += 1;
+                cur = cur.asCons().rest;
+                if (count > 256) break :blk null; // safety limit
+            }
+            if (cur == Value.nil_val or cur.tag() == .list) {
+                if (cur.tag() == .list) count += cur.asList().count();
+                break :blk count;
+            }
+            break :blk null; // lazy tail
+        },
+        else => null, // lazy_seq — can't know without realization
     };
 }