[MOD] Optimizations: mayBe(Array|Map|Function) checks unified

ChristianGruen · ChristianGruen · commit be017451ef17 · 2026-02-04T19:37:02.000+01:00
diff --git a/basex-core/src/main/java/org/basex/query/expr/Arith.java b/basex-core/src/main/java/org/basex/query/expr/Arith.java
@@ -59,8 +59,8 @@ public Expr optimize(final CompileContext cc) throws QueryException {
     final boolean numbers = type1.isNumberOrUntyped() && type2.isNumberOrUntyped();
 
     final Type type = calc.type(type1, type2);
-    final boolean noArray = !st1.mayBeArray() && !st2.mayBeArray();
-    final boolean oneOrMore = noArray && st1.oneOrMore() && st2.oneOrMore();
+    final boolean noArrays = !st1.mayBeFunction() && !st2.mayBeFunction();
+    final boolean oneOrMore = noArrays && st1.oneOrMore() && st2.oneOrMore();
     exprType.assign(type, oneOrMore ? Occ.EXACTLY_ONE : Occ.ZERO_OR_ONE);
 
     Expr expr = emptyExpr();
@@ -72,7 +72,7 @@ public Expr optimize(final CompileContext cc) throws QueryException {
     if(expr == this && Function.COUNT.is(expr1) && calc == Calc.ADD && Function.COUNT.is(expr2)) {
       expr = cc.function(Function.COUNT, info, List.get(cc, info, expr1.arg(0), expr2.arg(0)));
     }
-    if(expr == this && numbers && noArray && st1.one() && st2.one()) {
+    if(expr == this && numbers && noArrays && st1.one() && st2.one()) {
       // example: number($a) + 0 → number($a)
       final Expr ex = calc.optimize(expr1, expr2, info, cc);
       if(ex != null) {
diff --git a/basex-core/src/main/java/org/basex/query/expr/CmpG.java b/basex-core/src/main/java/org/basex/query/expr/CmpG.java
@@ -105,7 +105,7 @@ public final Expr optimize(final CompileContext cc) throws QueryException {
       }
 
       // choose best implementation
-      if(st1.zeroOrOne() && !st1.mayBeArray() && st2.zeroOrOne() && !st2.mayBeArray()) {
+      if(st1.zeroOrOne() && !st1.mayBeFunction() && st2.zeroOrOne() && !st2.mayBeFunction()) {
         // simple comparisons
         if(!(this instanceof CmpSimpleG)) expr = copyType(new CmpSimpleG(expr1, expr2, op, info));
       } else if(op == CmpOp.EQ && sc().collation == null && !st2.zeroOrOne() && (
@@ -242,7 +242,7 @@ final boolean eval(final Item item1, final Item item2) throws QueryException {
   public final CmpG invert() {
     final Expr expr1 = exprs[0], expr2 = exprs[1];
     final SeqType st1 = expr1.seqType(), st2 = expr2.seqType();
-    return st1.one() && !st1.mayBeArray() && st2.one() && !st2.mayBeArray() ?
+    return st1.one() && !st1.mayBeFunction() && st2.one() && !st2.mayBeFunction() ?
       new CmpG(info, expr1, expr2, op.invert()) : null;
   }
 
diff --git a/basex-core/src/main/java/org/basex/query/expr/CmpIR.java b/basex-core/src/main/java/org/basex/query/expr/CmpIR.java
@@ -109,7 +109,7 @@ public Expr optimize(final CompileContext cc) throws QueryException {
     expr = expr.simplifyFor(Simplify.NUMBER, cc);
 
     final SeqType st = expr.seqType();
-    single = st.zeroOrOne() && !st.mayBeArray();
+    single = st.zeroOrOne() && !st.mayBeFunction();
 
     // position() = 1 to 2 → pos: 1, 2
     if(Function.POSITION.is(expr)) return cc.replaceWith(this, IntPos.get(min, max, info));
diff --git a/basex-core/src/main/java/org/basex/query/expr/CmpR.java b/basex-core/src/main/java/org/basex/query/expr/CmpR.java
@@ -120,7 +120,7 @@ public Expr optimize(final CompileContext cc) throws QueryException {
     expr = expr.simplifyFor(Simplify.NUMBER, cc);
 
     final SeqType st = expr.seqType();
-    single = st.zeroOrOne() && !st.mayBeArray();
+    single = st.zeroOrOne() && !st.mayBeFunction();
 
     // position() = .1e0 → false()
     if(Function.POSITION.is(expr)) {
diff --git a/basex-core/src/main/java/org/basex/query/expr/CmpSR.java b/basex-core/src/main/java/org/basex/query/expr/CmpSR.java
@@ -64,7 +64,7 @@ public Expr optimize(final CompileContext cc) throws QueryException {
     expr = expr.simplifyFor(Simplify.STRING, cc);
 
     final SeqType st = expr.seqType();
-    single = st.zeroOrOne() && !st.mayBeArray();
+    single = st.zeroOrOne() && !st.mayBeFunction();
 
     return expr instanceof Value ? cc.preEval(this) : this;
   }
diff --git a/basex-core/src/main/java/org/basex/query/expr/CmpV.java b/basex-core/src/main/java/org/basex/query/expr/CmpV.java
@@ -55,7 +55,7 @@ public Expr optimize(final CompileContext cc) throws QueryException {
     if(expr == this) {
       // restrict type
       final SeqType st1 = exprs[0].seqType(), st2 = exprs[1].seqType();
-      if(st1.oneOrMore() && !st1.mayBeArray() && st2.oneOrMore() && !st2.mayBeArray()) {
+      if(st1.oneOrMore() && !st1.mayBeFunction() && st2.oneOrMore() && !st2.mayBeFunction()) {
         exprType.assign(Occ.EXACTLY_ONE);
       }
     }
@@ -121,7 +121,7 @@ private boolean test(final Item item1, final Item item2) throws QueryException {
   public Expr invert() {
     final Expr expr1 = exprs[0], expr2 = exprs[1];
     final SeqType st1 = expr1.seqType(), st2 = expr2.seqType();
-    return st1.one() && !st1.mayBeArray() && st2.one() && !st2.mayBeArray() ?
+    return st1.one() && !st1.mayBeFunction() && st2.one() && !st2.mayBeFunction() ?
       new CmpV(info, expr1, expr2, op.invert()) : null;
   }
 
diff --git a/basex-core/src/main/java/org/basex/query/expr/Convert.java b/basex-core/src/main/java/org/basex/query/expr/Convert.java
@@ -47,7 +47,7 @@ public final SeqType castType() {
     if(type instanceof ListType) {
       type = type.atomic();
       occ = Occ.ZERO_OR_MORE;
-    } else if(occ == Occ.ZERO_OR_ONE && est.oneOrMore() && !est.mayBeArray()) {
+    } else if(occ == Occ.ZERO_OR_ONE && est.oneOrMore() && !est.mayBeFunction()) {
       occ = Occ.EXACTLY_ONE;
     }
     return SeqType.get(type, occ);
@@ -60,7 +60,7 @@ public final SeqType castType() {
    */
   final Boolean castable(final SeqType castType) {
     final SeqType est = expr.seqType();
-    if(!est.mayBeArray()) {
+    if(!est.mayBeFunction()) {
       final long es = expr.size();
       if(es != -1 && (es < castType.occ.min || es > castType.occ.max)) return false;
 
@@ -80,7 +80,7 @@ final Boolean castable(final SeqType castType) {
   final Expr simplify(final SeqType castType, final CompileContext cc) {
     final SeqType est = expr.seqType();
     Expr arg = null;
-    if(est.one() && !est.mayBeArray() && castType.type.instanceOf(BasicType.NUMERIC)) {
+    if(est.one() && !est.mayBeFunction() && castType.type.instanceOf(BasicType.NUMERIC)) {
       // xs:int(string(I))
       // xs:int(xs:double(I)) → xs:int(I)
       arg = FnNumber.simplify(expr, cc);
diff --git a/basex-core/src/main/java/org/basex/query/expr/Expr.java b/basex-core/src/main/java/org/basex/query/expr/Expr.java
@@ -102,7 +102,7 @@ public Iter atomIter(final QueryContext qc, final InputInfo ii) throws QueryExce
     final SeqType st = seqType();
     if(st.type.instanceOf(BasicType.ANY_ATOMIC_TYPE)) return iter;
     long size = iter.size();
-    if(size != -1 && st.mayBeArray()) size = -1;
+    if(size != -1 && st.mayBeFunction()) size = -1;
     return new AtomIter(iter, qc, ii, size);
   }
 
diff --git a/basex-core/src/main/java/org/basex/query/expr/Lookup.java b/basex-core/src/main/java/org/basex/query/expr/Lookup.java
@@ -55,7 +55,7 @@ public Expr optimize(final CompileContext cc) throws QueryException {
     final SeqType kt = keys.seqType();
     final SeqType st = map ? ((MapType) tp).valueType() : ((ArrayType) tp).valueType();
     Occ occ = st.occ;
-    if(inputs.size() != 1 || keys == WILDCARD || !kt.one() || kt.mayBeArray()) {
+    if(inputs.size() != 1 || keys == WILDCARD || !kt.one() || kt.mayBeFunction()) {
       // key is wildcard, or expressions yield no single item
       occ = occ.union(Occ.ZERO_OR_MORE);
     } else if(map) {
@@ -75,7 +75,7 @@ public Expr optimize(final CompileContext cc) throws QueryException {
   private Expr opt(final CompileContext cc) throws QueryException {
     final Expr input = exprs[0], keys = exprs[1];
     final long is = input.size();
-    final long ks = keys.seqType().mayBeArray() || keys.has(Flag.NDT) ? -1 : keys.size();
+    final long ks = keys.seqType().mayBeFunction() || keys.has(Flag.NDT) ? -1 : keys.size();
     if(ks == 0) return keys;
 
     final Type it = input.seqType().type;
diff --git a/basex-core/src/main/java/org/basex/query/expr/TypeCheck.java b/basex-core/src/main/java/org/basex/query/expr/TypeCheck.java
@@ -52,7 +52,7 @@ public Expr optimize(final CompileContext cc) throws QueryException {
     cardinality = nst.instanceOf(st);
 
     // refine type check (ignore arrays as coerced result may have a different size)
-    if(!et.mayBeArray() || !type.instanceOf(BasicType.ANY_ATOMIC_TYPE)) {
+    if(!et.mayBeFunction() || !type.instanceOf(BasicType.ANY_ATOMIC_TYPE)) {
       // occurrence indicator:
       //   exactly-one/one-or-more → exactly-one
       final Occ nocc = et.occ.intersect(st.occ);
diff --git a/basex-core/src/main/java/org/basex/query/expr/Unary.java b/basex-core/src/main/java/org/basex/query/expr/Unary.java
@@ -41,7 +41,7 @@ public Expr optimize(final CompileContext cc) throws QueryException {
     final SeqType st = expr.seqType();
     final Type type = st.type.isUntyped() ? BasicType.DOUBLE :
       st.type.instanceOf(BasicType.INTEGER) ? BasicType.INTEGER : st.type;
-    final Occ occ = st.oneOrMore() && !st.mayBeArray() ? Occ.EXACTLY_ONE : Occ.ZERO_OR_ONE;
+    final Occ occ = st.oneOrMore() && !st.mayBeFunction() ? Occ.EXACTLY_ONE : Occ.ZERO_OR_ONE;
     exprType.assign(type, occ);
 
     // --123 → 123
diff --git a/basex-core/src/main/java/org/basex/query/expr/constr/CTxt.java b/basex-core/src/main/java/org/basex/query/expr/constr/CTxt.java
@@ -42,7 +42,7 @@ public Expr optimize(final CompileContext cc) throws QueryException {
     final SeqType st = expr.seqType();
     if(st.zero()) return cc.replaceWith(this, expr);
 
-    final boolean atom = !st.mayBeArray();
+    final boolean atom = !st.mayBeFunction();
     if(st.oneOrMore() && atom) exprType.assign(Occ.EXACTLY_ONE);
     return this;
   }
diff --git a/basex-core/src/main/java/org/basex/query/expr/gflwor/For.java b/basex-core/src/main/java/org/basex/query/expr/gflwor/For.java
@@ -122,7 +122,7 @@ public boolean next(final QueryContext qc) throws QueryException {
   public For optimize(final CompileContext cc) throws QueryException {
     // for $a as xs:integer in $array → for $a as xs:integer in data($array)
     final SeqType dt = var.declType;
-    if(dt != null && dt.instanceOf(Types.ANY_ATOMIC_TYPE_ZM) && expr.seqType().mayBeArray()) {
+    if(dt != null && dt.instanceOf(Types.ANY_ATOMIC_TYPE_ZM) && expr.seqType().mayBeFunction()) {
       expr = cc.function(DATA, info, expr);
     }
 
diff --git a/basex-core/src/main/java/org/basex/query/expr/gflwor/GroupBy.java b/basex-core/src/main/java/org/basex/query/expr/gflwor/GroupBy.java
@@ -302,7 +302,7 @@ GroupSpec group() {
     if(specs.length == 1 && post.length == 0) {
       final GroupSpec spec = specs[0];
       final SeqType st = spec.expr.seqType();
-      if(spec.coll == null && spec.var.declType == null && st.one() && !st.mayBeArray()) {
+      if(spec.coll == null && spec.var.declType == null && st.one() && !st.mayBeFunction()) {
         return spec;
       }
     }
diff --git a/basex-core/src/main/java/org/basex/query/expr/gflwor/OrderBy.java b/basex-core/src/main/java/org/basex/query/expr/gflwor/OrderBy.java
@@ -135,7 +135,7 @@ boolean merge(final For fr, final CompileContext cc) throws QueryException {
     if(keys.length == 1 && keys[0].coll == null && keys[0].least) {
       final Expr expr = keys[0].expr;
       // do not rewrite array keys (as they may contain sequences)
-      if(expr.seqType().mayBeArray()) return false;
+      if(expr.seqType().mayBeFunction()) return false;
       // for $i in 1 to 2 order by 1 return $i → for $i in 1 to 2 return $i
       if(expr instanceof Item) return true;
       // for $i in 1 to 2 order by $i return $i → for $i in sort(1 to 2) return $i
diff --git a/basex-core/src/main/java/org/basex/query/func/StandardFunc.java b/basex-core/src/main/java/org/basex/query/func/StandardFunc.java
@@ -142,7 +142,7 @@ protected final Expr optFirst(final boolean occ, final boolean atom, final Value
     if(expr != null) {
       final SeqType st = expr.seqType();
       if(st.zero()) return expr instanceof Dummy ? Empty.VALUE : expr;
-      if(occ && st.oneOrMore() && !(atom && st.mayBeArray()) && exprType.seqType().zeroOrOne()) {
+      if(occ && st.oneOrMore() && !(atom && st.mayBeFunction()) && exprType.seqType().zeroOrOne()) {
         exprType.assign(Occ.EXACTLY_ONE);
       }
     }
diff --git a/basex-core/src/main/java/org/basex/query/func/array/ArrayFlatten.java b/basex-core/src/main/java/org/basex/query/func/array/ArrayFlatten.java
@@ -71,7 +71,7 @@ public Value value(final QueryContext qc) throws QueryException {
   protected Expr opt(final CompileContext cc) {
     final Expr input = arg(0);
     final SeqType st = input.seqType();
-    if(!st.mayBeArray()) return input;
+    if(!st.mayBeFunction()) return input;
     exprType.assign(type(st.type));
     return this;
   }
diff --git a/basex-core/src/main/java/org/basex/query/func/fn/FnAllDifferent.java b/basex-core/src/main/java/org/basex/query/func/fn/FnAllDifferent.java
@@ -44,7 +44,7 @@ protected Expr opt(final CompileContext cc) throws QueryException {
     if(!defined(1)) {
       final SeqType st = values.seqType();
       final BasicType type = st.type.atomic();
-      if(st.zero() || st.zeroOrOne() && type != null && !st.mayBeArray())
+      if(st.zero() || st.zeroOrOne() && type != null && !st.mayBeFunction())
         return cc.voidAndReturn(values, Bln.TRUE, info);
 
       // all-different(1 to 10) → true
diff --git a/basex-core/src/main/java/org/basex/query/func/fn/FnAllEqual.java b/basex-core/src/main/java/org/basex/query/func/fn/FnAllEqual.java
@@ -47,7 +47,7 @@ protected Expr opt(final CompileContext cc) throws QueryException {
     if(!defined(1)) {
       final SeqType st = values.seqType();
       final BasicType type = st.type.atomic();
-      if(st.zero() || st.zeroOrOne() && type != null && !st.mayBeArray())
+      if(st.zero() || st.zeroOrOne() && type != null && !st.mayBeFunction())
         return cc.voidAndReturn(values, Bln.TRUE, info);
 
       // all-equal(1 to 10) → false
diff --git a/basex-core/src/main/java/org/basex/query/func/fn/FnAtomicEqual.java b/basex-core/src/main/java/org/basex/query/func/fn/FnAtomicEqual.java
@@ -29,8 +29,8 @@ protected Expr opt(final CompileContext cc) throws QueryException {
 
     // convert function call to general comparison (covers the most common cases)
     // atomic-equal(2, 3) → 2 = 3
-    if(sc().collation == null && st1.one() && st2.one() && !st1.mayBeArray() &&
-        !st2.mayBeArray() && tp1 != null && tp2 != null) {
+    if(sc().collation == null && st1.one() && st2.one() && !st1.mayBeFunction() &&
+        !st2.mayBeFunction() && tp1 != null && tp2 != null) {
       if(tp1.oneOf(BasicType.UNTYPED_ATOMIC, BasicType.ANY_URI)) tp1 = BasicType.STRING;
       if(tp2.oneOf(BasicType.UNTYPED_ATOMIC, BasicType.ANY_URI)) tp2 = BasicType.STRING;
       if(tp1 == tp2 && (tp1.oneOf(BasicType.QNAME, BasicType.BOOLEAN) ||
diff --git a/basex-core/src/main/java/org/basex/query/func/fn/FnAvg.java b/basex-core/src/main/java/org/basex/query/func/fn/FnAvg.java
@@ -29,7 +29,7 @@ protected Expr opt(final CompileContext cc) throws QueryException {
     if(expr != null) return expr;
 
     final SeqType st = arg(0).seqType();
-    if(!st.mayBeArray()) exprType.assign(Calc.DIVIDE.type(st.type, st.type));
+    if(!st.mayBeFunction()) exprType.assign(Calc.DIVIDE.type(st.type, st.type));
 
     return this;
   }
diff --git a/basex-core/src/main/java/org/basex/query/func/fn/FnCodepointEqual.java b/basex-core/src/main/java/org/basex/query/func/fn/FnCodepointEqual.java
@@ -50,7 +50,7 @@ protected Expr opt(final CompileContext cc) {
     final SeqType st1 = value1.seqType(), st2 = value2.seqType();
     if(st1.zero()) return value1;
     if(st2.zero()) return value2;
-    if(st1.oneOrMore() && !st1.mayBeArray() && st2.oneOrMore() && !st2.mayBeArray())
+    if(st1.oneOrMore() && !st1.mayBeFunction() && st2.oneOrMore() && !st2.mayBeFunction())
       exprType.assign(Occ.EXACTLY_ONE);
     return this;
   }
diff --git a/basex-core/src/main/java/org/basex/query/func/fn/FnCompare.java b/basex-core/src/main/java/org/basex/query/func/fn/FnCompare.java
@@ -37,7 +37,7 @@ protected Expr opt(final CompileContext cc) {
     final SeqType st1 = value1.seqType(), st2 = value2.seqType();
     if(st1.zero()) return value1;
     if(st2.zero()) return value2;
-    if(st1.oneOrMore() && !st1.mayBeArray() && st2.oneOrMore() && !st2.mayBeArray())
+    if(st1.oneOrMore() && !st1.mayBeFunction() && st2.oneOrMore() && !st2.mayBeFunction())
       exprType.assign(Occ.EXACTLY_ONE);
     return this;
   }
diff --git a/basex-core/src/main/java/org/basex/query/func/fn/FnData.java b/basex-core/src/main/java/org/basex/query/func/fn/FnData.java
@@ -47,7 +47,7 @@ protected Expr opt(final CompileContext cc) {
       }
       // ignore arrays: data((1 to 6) ! [ ., . ])
       if(type != null) {
-        exprType.assign(SeqType.get(type, st.occ), st.mayBeArray() ? -1 : input.size());
+        exprType.assign(SeqType.get(type, st.occ), st.mayBeFunction() ? -1 : input.size());
       }
     }
     return this;
@@ -70,7 +70,7 @@ public Expr simplifyFor(final Simplify mode, final CompileContext cc) throws Que
     } else if(mode == Simplify.COUNT) {
       // count(data($x)) → count($x)
       // do not simplify array input: count(data([ 1, 2, 3 ]))
-      if(!input.seqType().mayBeArray()) expr = input;
+      if(!input.seqType().mayBeFunction()) expr = input;
     } else if(mode.oneOf(Simplify.EBV, Simplify.PREDICATE)) {
       // if(data($node)) → if($node/descendant::text())
       expr = simplifyEbv(input, cc, null);
diff --git a/basex-core/src/main/java/org/basex/query/func/fn/FnDateTime.java b/basex-core/src/main/java/org/basex/query/func/fn/FnDateTime.java
@@ -34,8 +34,8 @@ protected Expr opt(final CompileContext cc) {
     final SeqType stDate = date.seqType(), stTime = time.seqType();
     if(stDate.zero()) return date;
     if(stTime.zero()) return time;
-    if(stDate.oneOrMore() && !stDate.mayBeArray() && stTime.oneOrMore() && !stTime.mayBeArray())
-      exprType.assign(Occ.EXACTLY_ONE);
+    if(stDate.oneOrMore() && !stDate.mayBeFunction() && stTime.oneOrMore() &&
+        !stTime.mayBeFunction()) exprType.assign(Occ.EXACTLY_ONE);
     return this;
   }
 }
diff --git a/basex-core/src/main/java/org/basex/query/func/fn/FnDistinctValues.java b/basex-core/src/main/java/org/basex/query/func/fn/FnDistinctValues.java
@@ -117,7 +117,7 @@ protected Expr opt(final CompileContext cc) throws QueryException {
         if(values instanceof Range || values instanceof RangeSeq) return values;
         // distinct-values($string) → $string
         // distinct-values($node) → data($node)
-        if(st.zeroOrOne() && !st.mayBeArray())
+        if(st.zeroOrOne() && !st.mayBeFunction())
           return type == st.type ? values : cc.function(DATA, info, exprs);
       }
       // assign atomic type of argument
diff --git a/basex-core/src/main/java/org/basex/query/func/fn/FnDuplicateValues.java b/basex-core/src/main/java/org/basex/query/func/fn/FnDuplicateValues.java
@@ -99,7 +99,7 @@ protected Expr opt(final CompileContext cc) throws QueryException {
         if(values instanceof RangeSeq || values instanceof Range || st.zeroOrOne())
           return Empty.VALUE;
         // util:duplicates((1 to 3) ! 1) → 1
-        if(values instanceof final SingletonSeq ss && !st.mayBeArray() && ss.singleItem()) {
+        if(values instanceof final SingletonSeq ss && !st.mayBeFunction() && ss.singleItem()) {
           return type == st.type ? ss.itemAt(0) : cc.function(Function.DATA, info, ss.itemAt(0));
         }
       }
diff --git a/basex-core/src/main/java/org/basex/query/func/fn/FnIndexOf.java b/basex-core/src/main/java/org/basex/query/func/fn/FnIndexOf.java
@@ -42,7 +42,7 @@ protected Expr opt(final CompileContext cc) {
     final Expr input = arg(0);
     final SeqType st = input.seqType();
     if(st.zero()) return input;
-    if(st.zeroOrOne() && !st.mayBeArray()) exprType.assign(Occ.ZERO_OR_ONE);
+    if(st.zeroOrOne() && !st.mayBeFunction()) exprType.assign(Occ.ZERO_OR_ONE);
     return this;
   }
 }
diff --git a/basex-core/src/main/java/org/basex/query/func/fn/FnItemsAt.java b/basex-core/src/main/java/org/basex/query/func/fn/FnItemsAt.java
@@ -108,7 +108,7 @@ protected Expr opt(final CompileContext cc) throws QueryException {
     if(ast.zero()) return Empty.VALUE;
 
     Occ occ = ast.zeroOrOne() ? Occ.ZERO_OR_ONE : Occ.ZERO_OR_MORE;
-    if(at instanceof Item && !ast.mayBeArray()) {
+    if(at instanceof Item && !ast.mayBeFunction()) {
       // check for fractional or negative number
       final double d = toDouble(at, cc.qc) - 1;
       final long l = (long) d;
diff --git a/basex-core/src/main/java/org/basex/query/func/fn/FnSum.java b/basex-core/src/main/java/org/basex/query/func/fn/FnSum.java
@@ -42,15 +42,15 @@ protected Expr opt(final CompileContext cc) throws QueryException {
     if(zero == Empty.UNDEFINED) {
       // no default value
       if(st.zero()) return cc.voidAndReturn(values, Itr.ZERO, info);
-      if(!st.mayBeArray()) {
+      if(!st.mayBeFunction()) {
         final SeqType ost = optType(values);
         if(ost != null) exprType.assign(ost);
       }
     } else if(st.zero()) {
       if(zero == Empty.VALUE || stZero.instanceOf(Types.ANY_ATOMIC_TYPE_ZO)) {
         return cc.voidAndReturn(values, zero, info);
       }
-    } else if(!st.mayBeArray() && !stZero.mayBeArray()) {
+    } else if(!st.mayBeFunction() && !stZero.mayBeFunction()) {
       if(st.oneOrMore()) return cc.function(Function.SUM, info, values);
       final SeqType ost = optType(values), zst = optType(zero);
       final Type type = ost != null && zst != null ? ost.type.union(zst.type) : ANY_ATOMIC_TYPE;
diff --git a/basex-core/src/main/java/org/basex/query/func/map/MapBuild.java b/basex-core/src/main/java/org/basex/query/func/map/MapBuild.java
@@ -71,7 +71,7 @@ public long structSize() {
     final Expr input = arg(0), keys = arg(1);
     final SeqType st = input.seqType();
     final long size = input.size();
-    return keys.size() == 0 && (size == 1 && !st.mayBeArray() && st.type.atomic() != null ||
+    return keys.size() == 0 && (size == 1 && !st.mayBeFunction() && st.type.atomic() != null ||
         input instanceof RangeSeq) ? size : -1;
   }
 
diff --git a/basex-core/src/main/java/org/basex/query/value/type/SeqType.java b/basex-core/src/main/java/org/basex/query/value/type/SeqType.java
@@ -455,31 +455,16 @@ public boolean oneOrMore() {
    * @return result of check
    */
   public boolean mayBeNumber() {
-    return !zero() && (type.isNumber() || ANY_ATOMIC_TYPE.instanceOf(type));
+    return !zero() && (type.isNumber() || type == BasicType.ANY_ATOMIC_TYPE ||
+        type == BasicType.ITEM);
   }
 
   /**
-   * Tests if expressions of this type may yield arrays.
-   * @return result of check
-   */
-  public boolean mayBeArray() {
-    return !zero() && (type instanceof ArrayType || Types.ARRAY.instanceOf(type));
-  }
-
-  /**
-   * Tests if expressions of this type may yield maps.
-   * @return result of check
-   */
-  public boolean mayBeMap() {
-    return !zero() && (type instanceof MapType || Types.MAP.instanceOf(type));
-  }
-
-  /**
-   * Tests if expressions of this type may yield functions.
+   * Tests if expressions of this type may yield functions (including maps and arrays).
    * @return result of check
    */
   public boolean mayBeFunction() {
-    return !zero() && (type instanceof FType || type == BasicType.ITEM);
+    return !zero() && (type == BasicType.ITEM || type instanceof FType);
   }
 
   /**
diff --git a/basex-core/src/test/java/org/basex/query/SeqTypeTest.java b/basex-core/src/test/java/org/basex/query/SeqTypeTest.java

Original file line number	Diff line number	Diff line change
`@@ -64,7 +64,7 @@ public Expr optimize(final CompileContext cc) throws QueryException {`
`64`	`64`	`expr = expr.simplifyFor(Simplify.STRING, cc);`
`65`	`65`
`66`	`66`	`final SeqType st = expr.seqType();`
`67`		`- single = st.zeroOrOne() && !st.mayBeArray();`
	`67`	`+ single = st.zeroOrOne() && !st.mayBeFunction();`
`68`	`68`
`69`	`69`	`return expr instanceof Value ? cc.preEval(this) : this;`
`70`	`70`	`}`
Original file line number	Diff line number	Diff line change
`@@ -55,7 +55,7 @@ public Expr optimize(final CompileContext cc) throws QueryException {`
`55`	`55`	`if(expr == this) {`
`56`	`56`	`// restrict type`
`57`	`57`	`final SeqType st1 = exprs[0].seqType(), st2 = exprs[1].seqType();`
`58`		`- if(st1.oneOrMore() && !st1.mayBeArray() && st2.oneOrMore() && !st2.mayBeArray()) {`
	`58`	`+ if(st1.oneOrMore() && !st1.mayBeFunction() && st2.oneOrMore() && !st2.mayBeFunction()) {`
`59`	`59`	`exprType.assign(Occ.EXACTLY_ONE);`
`60`	`60`	`}`
`61`	`61`	`}`
`@@ -121,7 +121,7 @@ private boolean test(final Item item1, final Item item2) throws QueryException {`
`121`	`121`	`public Expr invert() {`
`122`	`122`	`final Expr expr1 = exprs[0], expr2 = exprs[1];`
`123`	`123`	`final SeqType st1 = expr1.seqType(), st2 = expr2.seqType();`
`124`		`- return st1.one() && !st1.mayBeArray() && st2.one() && !st2.mayBeArray() ?`
	`124`	`+ return st1.one() && !st1.mayBeFunction() && st2.one() && !st2.mayBeFunction() ?`
`125`	`125`	`new CmpV(info, expr1, expr2, op.invert()) : null;`
`126`	`126`	`}`
`127`	`127`
Original file line number	Diff line number	Diff line change
`@@ -102,7 +102,7 @@ public Iter atomIter(final QueryContext qc, final InputInfo ii) throws QueryExce`
`102`	`102`	`final SeqType st = seqType();`
`103`	`103`	`if(st.type.instanceOf(BasicType.ANY_ATOMIC_TYPE)) return iter;`
`104`	`104`	`long size = iter.size();`
`105`		`- if(size != -1 && st.mayBeArray()) size = -1;`
	`105`	`+ if(size != -1 && st.mayBeFunction()) size = -1;`
`106`	`106`	`return new AtomIter(iter, qc, ii, size);`
`107`	`107`	`}`
`108`	`108`