Fix #1274

jit-compiler/src/main/java/org/aya/compiler/free/Constants.java

@@ -1,4 +1,4 @@
-// Copyright (c) 2020-2024 Tesla (Yinsen) Zhang.
+// Copyright (c) 2020-2025 Tesla (Yinsen) Zhang.
 // Use of this source code is governed by the MIT license that can be found in the LICENSE.md file.
 package org.aya.compiler.free;
 
@@ -39,6 +39,8 @@ private Constants() { }
   public static final @NotNull ClassDesc CD_MutableSeq = FreeUtil.fromClass(MutableSeq.class);
   public static final @NotNull ClassDesc CD_Thunk = FreeUtil.fromClass(Supplier.class);
   public static final @NotNull ClassDesc CD_Result = FreeUtil.fromClass(Result.class);
+  public static final @NotNull String NAME_OF = "of";
+  public static final @NotNull String NAME_EMPTY = "empty";
 
   // Term -> Term
   public static final @NotNull MethodRef CLOSURE = new MethodRef(
@@ -63,10 +65,10 @@ private Constants() { }
     true
   );
 
-  // ImmutableSeq from(Object[])
+  /// @see ImmutableSeq#of(Object[])
   public static final @NotNull MethodRef IMMSEQ = new MethodRef(
     CD_ImmutableSeq,
-    "from",
+    NAME_OF,
     CD_ImmutableSeq, ImmutableSeq.of(ConstantDescs.CD_Object.arrayType()),
     true
   );
@@ -110,7 +112,7 @@ private Constants() { }
 
   public static final @NotNull MethodRef IMMTREESEQ = new MethodRef(
     FreeUtil.fromClass(ImmutableTreeSeq.class),
-    "from",
+    NAME_OF,
     FreeUtil.fromClass(ImmutableTreeSeq.class),
     ImmutableSeq.of(ConstantDescs.CD_Object.arrayType()),
     false

jit-compiler/src/main/java/org/aya/compiler/serializers/AbstractExprializer.java

@@ -1,4 +1,4 @@
-// Copyright (c) 2020-2024 Tesla (Yinsen) Zhang.
+// Copyright (c) 2020-2025 Tesla (Yinsen) Zhang.
 // Use of this source code is governed by the MIT license that can be found in the LICENSE.md file.
 package org.aya.compiler.serializers;
 
@@ -10,6 +10,7 @@
 import org.jetbrains.annotations.NotNull;
 
 import java.lang.constant.ClassDesc;
+import java.lang.constant.ConstantDescs;
 
 public abstract class AbstractExprializer<T> {
   protected final @NotNull FreeExprBuilder builder;
@@ -39,14 +40,48 @@ public abstract class AbstractExprializer<T> {
     return makeImmutableSeq(builder, Constants.IMMSEQ, typeName, terms);
   }
 
+  /// @param con the factory function used for constructing an {@link ImmutableSeq}, usually it is {@link ImmutableSeq#of}.
+  ///                       This function may re-resolve the factory function to fixed size parameters one
+  ///                       with the name of {@param con}
+  ///                       in case {@param terms} is very small.
+  /// @see ImmutableSeq#empty()
+  /// @see ImmutableSeq#of(Object)
+  /// @see ImmutableSeq#of(Object, Object)
+  /// @see ImmutableSeq#of(Object, Object, Object)
+  /// @see ImmutableSeq#of(Object, Object, Object, Object)
+  /// @see ImmutableSeq#of(Object, Object, Object, Object, Object)
+  /// @see ImmutableSeq#of(Object[])
   public static @NotNull FreeJavaExpr makeImmutableSeq(
     @NotNull FreeExprBuilder builder,
     @NotNull MethodRef con,
     @NotNull Class<?> typeName,
     @NotNull ImmutableSeq<FreeJavaExpr> terms
   ) {
-    var args = builder.mkArray(FreeUtil.fromClass(typeName), terms.size(), terms);
-    return builder.invoke(con, ImmutableSeq.of(args));
+    ImmutableSeq<FreeJavaExpr> args;
+
+    if (terms.size() <= 5) {
+      String name = con.name();
+      ImmutableSeq<ClassDesc> params;
+
+      // re-resolve
+      if (terms.isEmpty()) {
+        name = Constants.NAME_EMPTY;
+        params = ImmutableSeq.empty();
+      } else {
+        params = ImmutableSeq.fill(terms.size(), ConstantDescs.CD_Object);
+      }
+
+      con = FreeJavaResolver.resolve(
+        con.owner(), name,
+        con.returnType(), params,
+        con.isInterface());
+
+      args = terms;
+    } else {
+      args = ImmutableSeq.of(builder.mkArray(FreeUtil.fromClass(typeName), terms.size(), terms));
+    }
+
+    return builder.invoke(con, args);
   }
 
   /**

jit-compiler/src/main/java/org/aya/compiler/serializers/PatternSerializer.java

@@ -264,7 +264,7 @@ public PatternSerializer serialize(@NotNull FreeCodeBuilder builder, @NotNull Im
       assert i > 0;
       var realIdx = i - 1;
       unit.get(realIdx).onSucc.accept(this, mBuilder, bindSize.get(realIdx));
-    }, builder1 -> builder1.unreachable());
+    }, FreeCodeBuilder::unreachable);
 
     return this;
   }