Generalize dimension-wise

2 files changed, 8 insertions, 7 deletions

diff --git a/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/rule/IfNode.java b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/rule/IfNode.java
index 4f0ebc1c7e5..66b250736e8 100755
--- a/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/rule/IfNode.java
+++ b/searchlib/src/main/java/com/yahoo/searchlib/rankingexpression/rule/IfNode.java
@@ -78,13 +78,11 @@ public final class IfNode extends CompositeNode {
     public TensorType type(TypeContext context) {
         TensorType trueType = trueExpression.type(context);
         TensorType falseType = falseExpression.type(context);
-
-        // Types of each branch must be compatible; the resulting type is the most general
-        if (trueType.isAssignableTo(falseType)) return falseType;
-        if (falseType.isAssignableTo(trueType)) return trueType;
-        throw new IllegalArgumentException("An if expression must produce compatible types in both " +
-                                           "alternatives, but the 'true' type is " + trueType + " while the " +
-                                           "'false' type is " + falseType);
+        return trueType.dimensionwiseGeneralizationWith(falseType).orElseThrow(() ->
+            new IllegalArgumentException("An if expression must produce compatible types in both " +
+                                         "alternatives, but the 'true' type is " + trueType + " while the " +
+                                         "'false' type is " + falseType)
+        );
     }
 
     @Override
diff --git a/searchlib/src/test/java/com/yahoo/searchlib/rankingexpression/evaluation/TypeResolutionTestCase.java b/searchlib/src/test/java/com/yahoo/searchlib/rankingexpression/evaluation/TypeResolutionTestCase.java
index d1ea0fcf2e4..5cac2215a00 100644
--- a/searchlib/src/test/java/com/yahoo/searchlib/rankingexpression/evaluation/TypeResolutionTestCase.java
+++ b/searchlib/src/test/java/com/yahoo/searchlib/rankingexpression/evaluation/TypeResolutionTestCase.java
@@ -22,9 +22,12 @@ public class TypeResolutionTestCase {
         context.setType("query('x1')", TensorType.fromSpec("tensor(x[])"));
         context.setType("query('x2')", TensorType.fromSpec("tensor(x[10])"));
         context.setType("query('y1')", TensorType.fromSpec("tensor(y[])"));
+        context.setType("query('xy1')", TensorType.fromSpec("tensor(x[10],y[])"));
+        context.setType("query('xy2')", TensorType.fromSpec("tensor(x[],y[10])"));
 
         assertType("tensor(x[])", "query(x1)", context);
         assertType("tensor(x[])", "if (1>0, query(x1), query(x2))", context);
+        assertType("tensor(x[],y[])", "if (1>0, query(xy1), query(xy2))", context);
         assertIncompatibleType("if (1>0, query(x1), query(y1))", context);
     }