Make inputDataType final to ensure complete at construction time.

19 files changed, 88 insertions, 78 deletions

diff --git a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/ArithmeticExpression.java b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/ArithmeticExpression.java
index 02c68bdf967..68b9e79e092 100644
--- a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/ArithmeticExpression.java
+++ b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/ArithmeticExpression.java
@@ -46,8 +46,7 @@ public final class ArithmeticExpression extends CompositeExpression {
     private final Expression rhs;
 
     public ArithmeticExpression(Expression lhs, Operator op, Expression rhs) {
-        super(null);
-        setInputType(requiredInputType(lhs, rhs));
+        super(requiredInputType(lhs, rhs));
         lhs.getClass(); // throws NullPointerException
         op.getClass();
         rhs.getClass();
@@ -82,7 +81,7 @@ public final class ArithmeticExpression extends CompositeExpression {
                                   context.setValue(input).execute(rhs).getValue()));
     }
 
-    private DataType requiredInputType(Expression lhs, Expression rhs) {
+    private static DataType requiredInputType(Expression lhs, Expression rhs) {
         DataType lhsType = lhs.requiredInputType();
         DataType rhsType = rhs.requiredInputType();
         if (lhsType == null) {
@@ -92,7 +91,7 @@ public final class ArithmeticExpression extends CompositeExpression {
             return lhsType;
         }
         if (!lhsType.equals(rhsType)) {
-            throw new VerificationException(this, "Operands require conflicting input types, " +
+            throw new VerificationException(ArithmeticExpression.class, "Operands require conflicting input types, " +
                                                   lhsType.getName() + " vs " + rhsType.getName() + ".");
         }
         return lhsType;
diff --git a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/CatExpression.java b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/CatExpression.java
index be6b6db6a9a..f395446cb10 100644
--- a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/CatExpression.java
+++ b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/CatExpression.java
@@ -18,12 +18,11 @@ import java.util.*;
 public final class CatExpression extends ExpressionList<Expression> {
 
     public CatExpression(Expression... lst) {
-        super(Arrays.asList(lst));
-        setInputType(resolveInputType());
+        this(Arrays.asList(lst));
     }
 
     public CatExpression(Collection<? extends Expression> lst) {
-        super(lst);
+        super(lst, resolveInputType(lst));
     }
 
     @Override
@@ -63,17 +62,17 @@ public final class CatExpression extends ExpressionList<Expression> {
         context.setValue(resolveOutputType(types));
     }
 
-    private DataType resolveInputType() {
+    private static DataType resolveInputType(Collection<? extends Expression> list) {
         DataType prev = null;
-        for (Expression exp : this) {
+        for (Expression exp : list) {
             DataType next = exp.requiredInputType();
             if (next == null) {
                 // ignore
             } else if (prev == null) {
                 prev = next;
             } else if (!prev.isAssignableFrom(next)) {
-                throw new VerificationException(this, "Operands require conflicting input types, " +
-                                                      prev.getName() + " vs " + next.getName() + ".");
+                throw new VerificationException(CatExpression.class, "Operands require conflicting input types, " +
+                                                                      prev.getName() + " vs " + next.getName() + ".");
             }
         }
         return prev;
diff --git a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/Expression.java b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/Expression.java
index 3d8da1a8b77..231446b9c62 100644
--- a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/Expression.java
+++ b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/Expression.java
@@ -17,14 +17,12 @@ import com.yahoo.vespa.objects.Selectable;
  */
 public abstract class Expression extends Selectable {
 
-    private DataType inputType;
+    private final DataType inputType;
 
     protected Expression(DataType inputType) {
         this.inputType = inputType;
     }
-    protected void setInputType(DataType inputType) {
-        this.inputType = inputType;
-    }
+
     public final FieldValue execute(FieldValue val) {
         return execute(new ExecutionContext().setValue(val));
     }
diff --git a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/ExpressionList.java b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/ExpressionList.java
index 6c83835559c..ca929773a4c 100644
--- a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/ExpressionList.java
+++ b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/ExpressionList.java
@@ -1,6 +1,7 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 package com.yahoo.vespa.indexinglanguage.expressions;
 
+import com.yahoo.document.DataType;
 import com.yahoo.document.DocumentType;
 import com.yahoo.vespa.objects.ObjectOperation;
 import com.yahoo.vespa.objects.ObjectPredicate;
@@ -17,12 +18,8 @@ public abstract class ExpressionList<T extends Expression> extends CompositeExpr
 
     private final List<T> expressions = new LinkedList<T>();
 
-    protected ExpressionList() {
-        super(null);
-    }
-
-    protected ExpressionList(Iterable<? extends T> lst) {
-        super(null);
+    protected ExpressionList(Iterable<? extends T> lst, DataType inputType) {
+        super(inputType);
         for (T exp : lst) {
             this.expressions.add(exp);
         }
diff --git a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/IfThenExpression.java b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/IfThenExpression.java
index 16365e1264b..9e7f60aa3e3 100644
--- a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/IfThenExpression.java
+++ b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/IfThenExpression.java
@@ -46,13 +46,12 @@ public final class IfThenExpression extends CompositeExpression {
     }
 
     public IfThenExpression(Expression lhs, Comparator cmp, Expression rhs, Expression ifTrue, Expression ifFalse) {
-        super(null);
+        super(resolveInputType(lhs, rhs, ifTrue, ifFalse));
         this.lhs = lhs;
         this.cmp = cmp;
         this.rhs = rhs;
         this.ifTrue = ifTrue;
         this.ifFalse = ifFalse;
-        setInputType(resolveInputType());
     }
 
     public Expression getLeftHandSide() {
@@ -114,7 +113,7 @@ public final class IfThenExpression extends CompositeExpression {
         select(ifFalse, predicate, operation);
     }
 
-    private DataType resolveInputType() {
+    private static DataType resolveInputType(Expression lhs, Expression rhs, Expression ifTrue, Expression ifFalse) {
         DataType input = null;
         input = resolveRequiredInputType(input, lhs.requiredInputType());
         input = resolveRequiredInputType(input, rhs.requiredInputType());
@@ -174,7 +173,7 @@ public final class IfThenExpression extends CompositeExpression {
         return ret;
     }
 
-    private DataType resolveRequiredInputType(DataType prev, DataType next) {
+    private static DataType resolveRequiredInputType(DataType prev, DataType next) {
         if (next == null) {
             return prev;
         }
@@ -182,7 +181,7 @@ public final class IfThenExpression extends CompositeExpression {
             return next;
         }
         if (!prev.equals(next)) {
-            throw new VerificationException(this, "Operands require conflicting input types, " +
+            throw new VerificationException(IfThenExpression.class, "Operands require conflicting input types, " +
                                                   prev.getName() + " vs " + next.getName() + ".");
         }
         return prev;
diff --git a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/ScriptExpression.java b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/ScriptExpression.java
index 275ca58d4db..3e9f6ad5032 100644
--- a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/ScriptExpression.java
+++ b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/ScriptExpression.java
@@ -12,6 +12,7 @@ import com.yahoo.vespa.indexinglanguage.parser.ParseException;
 
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Iterator;
 
 /**
@@ -20,18 +21,15 @@ import java.util.Iterator;
 public final class ScriptExpression extends ExpressionList<StatementExpression> {
 
     public ScriptExpression() {
-        super();
-        setInputType(resolveInputType());
+        this(Collections.emptyList());
     }
 
     public ScriptExpression(StatementExpression... lst) {
-        super(Arrays.asList(lst));
-        setInputType(resolveInputType());
+        this(Arrays.asList(lst));
     }
 
     public ScriptExpression(Collection<? extends StatementExpression> lst) {
-        super(lst);
-        setInputType(resolveInputType());
+        super(lst, resolveInputType(lst));
     }
 
     @Override
@@ -52,14 +50,14 @@ public final class ScriptExpression extends ExpressionList<StatementExpression>
         context.setValue(input);
     }
 
-    private DataType resolveInputType() {
+    private static DataType resolveInputType(Collection<? extends StatementExpression> list) {
         DataType prev = null;
-        for (Expression exp : this) {
+        for (Expression exp : list) {
             DataType next = exp.requiredInputType();
             if (prev == null) {
                 prev = next;
             } else if (next != null && !prev.isAssignableFrom(next)) {
-                throw new VerificationException(this, "Statements require conflicting input types, " +
+                throw new VerificationException(ScriptExpression.class, "Statements require conflicting input types, " +
                                                       prev.getName() + " vs " + next.getName() + ".");
             }
         }
diff --git a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/StatementExpression.java b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/StatementExpression.java
index eb6b5563584..422457d18fa 100644
--- a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/StatementExpression.java
+++ b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/StatementExpression.java
@@ -10,6 +10,7 @@ import com.yahoo.vespa.indexinglanguage.parser.IndexingInput;
 import com.yahoo.vespa.indexinglanguage.parser.ParseException;
 
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Iterator;
 import java.util.LinkedList;
 import java.util.List;
@@ -21,12 +22,14 @@ public final class StatementExpression extends ExpressionList<Expression> {
 
     public StatementExpression(Expression... lst) {
         this(Arrays.asList(lst));
-        setInputType(resolveInputType());
     }
 
     public StatementExpression(Iterable<Expression> lst) {
-        super(filterList(lst));
-        setInputType(resolveInputType());
+        this(filterList(lst), null);
+    }
+
+    private StatementExpression(Iterable<Expression> list, Object unused) {
+        super(list, resolveInputType(list));
     }
 
     @Override
@@ -43,12 +46,13 @@ public final class StatementExpression extends ExpressionList<Expression> {
         }
     }
 
-    private DataType resolveInputType() {
-        for (Expression exp : this) {
+    private static DataType resolveInputType(Iterable<Expression> lst) {
+        for (Expression exp : lst) {
             DataType type = exp.requiredInputType();
             if (type != null) {
                 return type;
             }
+
             type = exp.createdOutputType();
             if (type != null) {
                 return null;
diff --git a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/VerificationException.java b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/VerificationException.java
index 32f337f500c..836600caa2b 100644
--- a/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/VerificationException.java
+++ b/indexinglanguage/src/main/java/com/yahoo/vespa/indexinglanguage/expressions/VerificationException.java
@@ -6,16 +6,33 @@ package com.yahoo.vespa.indexinglanguage.expressions;
  */
 public class VerificationException extends RuntimeException {
 
-    private final Expression exp;
+    private final Class<?> type;
+    private final String exp;
 
     public VerificationException(Expression exp, String msg) {
         super(msg);
-        this.exp = exp;
+        if (exp != null) {
+            this.type = exp.getClass();
+            this.exp = exp.toString();
+        } else {
+            this.type = null;
+            this.exp = "null";
+        }
     }
 
-    public Expression getExpression() {
+
+    public VerificationException(Class<?> exp, String msg) {
+        super(msg);
+        this.type = exp;
+        this.exp = exp.getName();
+    }
+
+    public String getExpression() {
         return exp;
     }
+    public Class<?> getExpressionType() {
+        return type;
+    }
 
     @Override
     public String toString() {
diff --git a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/ScriptTestCase.java b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/ScriptTestCase.java
index f3cd40d71c5..58e80b5eb2b 100644
--- a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/ScriptTestCase.java
+++ b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/ScriptTestCase.java
@@ -53,7 +53,7 @@ public class ScriptTestCase {
             exp.verify(input);
             fail();
         } catch (VerificationException e) {
-            assertTrue(e.getExpression() instanceof ScriptExpression);
+            assertTrue(e.getExpressionType().equals(ScriptExpression.class));
             assertEquals("Expected any input, got null.", e.getMessage());
         }
     }
diff --git a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/ArithmeticTestCase.java b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/ArithmeticTestCase.java
index c930f4e4d38..8b7ea5a141b 100644
--- a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/ArithmeticTestCase.java
+++ b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/ArithmeticTestCase.java
@@ -82,7 +82,7 @@ public class ArithmeticTestCase {
     @Test
     public void requireThatOperandInputCanBeNull() {
         SimpleExpression reqNull = new SimpleExpression();
-        SimpleExpression reqInt = new SimpleExpression().setRequiredInput(DataType.INT);
+        SimpleExpression reqInt = new SimpleExpression(DataType.INT);
         assertNull(newArithmetic(reqNull, Operator.ADD, reqNull).requiredInputType());
         assertEquals(DataType.INT, newArithmetic(reqInt, Operator.ADD, reqNull).requiredInputType());
         assertEquals(DataType.INT, newArithmetic(reqInt, Operator.ADD, reqInt).requiredInputType());
@@ -91,10 +91,10 @@ public class ArithmeticTestCase {
 
     @Test
     public void requireThatOperandsAreInputCompatible() {
-        assertVerify(new SimpleExpression().setRequiredInput(DataType.INT), Operator.ADD,
-                     new SimpleExpression().setRequiredInput(DataType.INT), DataType.INT);
-        assertVerifyThrows(new SimpleExpression().setRequiredInput(DataType.INT), Operator.ADD,
-                           new SimpleExpression().setRequiredInput(DataType.STRING), null,
+        assertVerify(new SimpleExpression(DataType.INT), Operator.ADD,
+                     new SimpleExpression(DataType.INT), DataType.INT);
+        assertVerifyThrows(new SimpleExpression(DataType.INT), Operator.ADD,
+                           new SimpleExpression(DataType.STRING), null,
                            "Operands require conflicting input types, int vs string.");
     }
 
diff --git a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/CatTestCase.java b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/CatTestCase.java
index e83c18786bc..1b9c546fa19 100644
--- a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/CatTestCase.java
+++ b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/CatTestCase.java
@@ -46,19 +46,19 @@ public class CatTestCase {
     public void requireThatExpressionCanBeVerified() {
         assertVerify(new SetValueExpression(new StringFieldValue("foo")),
                      new SetValueExpression(new StringFieldValue("bar")), null);
-        assertVerify(new SimpleExpression().setRequiredInput(DataType.STRING),
-                     new SimpleExpression().setRequiredInput(DataType.STRING), DataType.STRING);
+        assertVerify(new SimpleExpression(DataType.STRING),
+                     new SimpleExpression(DataType.STRING), DataType.STRING);
         assertVerifyThrows(new SimpleExpression().setCreatedOutput(null),
                            new SimpleExpression().setCreatedOutput(DataType.STRING), null,
                            "Attempting to concatenate a null value ");
-        assertVerifyThrows(new SimpleExpression().setRequiredInput(DataType.STRING),
-                           new SimpleExpression().setRequiredInput(DataType.INT), null,
+        assertVerifyThrows(new SimpleExpression(DataType.STRING),
+                           new SimpleExpression(DataType.INT), null,
                            "Operands require conflicting input types, string vs int.");
-        assertVerifyThrows(new SimpleExpression().setRequiredInput(DataType.STRING),
-                           new SimpleExpression().setRequiredInput(DataType.STRING), null,
+        assertVerifyThrows(new SimpleExpression(DataType.STRING),
+                           new SimpleExpression(DataType.STRING), null,
                            "Expected string input, got null.");
-        assertVerifyThrows(new SimpleExpression().setRequiredInput(DataType.STRING),
-                           new SimpleExpression().setRequiredInput(DataType.STRING), DataType.INT,
+        assertVerifyThrows(new SimpleExpression(DataType.STRING),
+                           new SimpleExpression(DataType.STRING), DataType.INT,
                            "Expected string input, got int.");
     }
 
diff --git a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/ExpressionTestCase.java b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/ExpressionTestCase.java
index c5ae67d1d47..902e091d17c 100644
--- a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/ExpressionTestCase.java
+++ b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/ExpressionTestCase.java
@@ -62,7 +62,7 @@ public class ExpressionTestCase {
     }
 
     private static Expression newRequiredInput(DataType requiredInput) {
-        return new SimpleExpression().setRequiredInput(requiredInput);
+        return new SimpleExpression(requiredInput);
     }
 
     private static Expression newCreatedOutput(DataType createdOutput, FieldValue actualOutput) {
diff --git a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/IfThenTestCase.java b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/IfThenTestCase.java
index 4d7f1cb02d1..95366111176 100644
--- a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/IfThenTestCase.java
+++ b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/IfThenTestCase.java
@@ -263,10 +263,10 @@ public class IfThenTestCase {
     }
 
     private static Expression newRequiredInput(DataType lhs, Comparator cmp, DataType rhs, DataType ifTrue, DataType ifFalse) {
-        return new IfThenExpression(new SimpleExpression().setRequiredInput(lhs), cmp,
-                                    new SimpleExpression().setRequiredInput(rhs),
-                                    new SimpleExpression().setRequiredInput(ifTrue),
-                                    ifFalse != null ? new SimpleExpression().setRequiredInput(ifFalse) : null);
+        return new IfThenExpression(new SimpleExpression(lhs), cmp,
+                                    new SimpleExpression(rhs),
+                                    new SimpleExpression(ifTrue),
+                                    ifFalse != null ? new SimpleExpression(ifFalse) : null);
     }
 
     private static class MyFieldValue extends FieldValue {
diff --git a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/OutputAssert.java b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/OutputAssert.java
index 7c0b2aa98a4..810863478ec 100644
--- a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/OutputAssert.java
+++ b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/OutputAssert.java
@@ -28,7 +28,7 @@ class OutputAssert {
         assertVerify(new MyAdapter(null), DataType.INT, exp);
         assertVerify(new MyAdapter(null), DataType.STRING, exp);
         assertVerifyThrows(new MyAdapter(null), null, exp, "Expected any input, got null.");
-        assertVerifyThrows(new MyAdapter(new VerificationException(null, "foo")), DataType.INT, exp, "foo");
+        assertVerifyThrows(new MyAdapter(new VerificationException((Expression) null, "foo")), DataType.INT, exp, "foo");
     }
 
     public static void assertVerify(FieldTypeAdapter adapter, DataType value, Expression exp) {
diff --git a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/SetVarTestCase.java b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/SetVarTestCase.java
index 66eb29796ad..85039260cb0 100644
--- a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/SetVarTestCase.java
+++ b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/SetVarTestCase.java
@@ -68,7 +68,7 @@ public class SetVarTestCase {
             new SetVarExpression("out").verify(ctx);
             fail();
         } catch (VerificationException e) {
-            assertTrue(e.getExpression() instanceof SetVarExpression);
+            assertTrue(e.getExpressionType().equals(SetVarExpression.class));
             assertEquals("Attempting to assign conflicting types to variable 'out', int vs string.", e.getMessage());
         }
     }
diff --git a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/SimpleExpression.java b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/SimpleExpression.java
index c771389ac1b..462189384c6 100644
--- a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/SimpleExpression.java
+++ b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/SimpleExpression.java
@@ -18,6 +18,10 @@ final class SimpleExpression extends Expression {
     public SimpleExpression() {
         super(null);
     }
+    public SimpleExpression(DataType requiredInput) {
+        super(requiredInput);
+    }
+
     public SimpleExpression setExecuteValue(FieldValue executeValue) {
         this.hasExecuteValue = true;
         this.executeValue = executeValue;
@@ -30,11 +34,6 @@ final class SimpleExpression extends Expression {
         return this;
     }
 
-    public SimpleExpression setRequiredInput(DataType requiredInput) {
-        setInputType(requiredInput);
-        return this;
-    }
-
     public SimpleExpression setCreatedOutput(DataType createdOutput) {
         this.createdOutput = createdOutput;
         return this;
@@ -92,16 +91,16 @@ final class SimpleExpression extends Expression {
     }
 
     public static SimpleExpression newOutput(DataType createdOutput) {
-        return new SimpleExpression().setCreatedOutput(createdOutput)
+        return new SimpleExpression(null).setCreatedOutput(createdOutput)
                                      .setVerifyValue(createdOutput);
     }
 
     public static SimpleExpression newRequired(DataType requiredInput) {
-        return new SimpleExpression().setRequiredInput(requiredInput);
+        return new SimpleExpression(requiredInput);
     }
 
     public static SimpleExpression newConversion(DataType requiredInput, DataType createdOutput) {
-        return new SimpleExpression().setRequiredInput(requiredInput)
+        return new SimpleExpression(requiredInput)
                                      .setCreatedOutput(createdOutput)
                                      .setExecuteValue(createdOutput.createFieldValue())
                                      .setVerifyValue(createdOutput);
diff --git a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/SimpleExpressionTestCase.java b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/SimpleExpressionTestCase.java
index 2644ed5af7a..27e96c63702 100644
--- a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/SimpleExpressionTestCase.java
+++ b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/SimpleExpressionTestCase.java
@@ -20,7 +20,7 @@ public class SimpleExpressionTestCase {
         assertNull(exp.execute());
         assertNull(exp.verify());
 
-        assertEquals(DataType.INT, new SimpleExpression().setRequiredInput(DataType.INT).requiredInputType());
+        assertEquals(DataType.INT, new SimpleExpression(DataType.INT).requiredInputType());
         assertEquals(DataType.INT, new SimpleExpression().setCreatedOutput(DataType.INT).createdOutputType());
         assertEquals(DataType.INT, new SimpleExpression().setVerifyValue(DataType.INT).verify());
         assertEquals(new IntegerFieldValue(69),
@@ -50,9 +50,9 @@ public class SimpleExpressionTestCase {
         assertFalse(exp.equals(new SimpleExpression().setVerifyValue(DataType.STRING)));
         assertEquals(exp, new SimpleExpression().setVerifyValue(DataType.INT));
 
-        exp = new SimpleExpression().setRequiredInput(DataType.INT);
-        assertFalse(exp.equals(new SimpleExpression().setRequiredInput(DataType.STRING)));
-        assertEquals(exp, new SimpleExpression().setRequiredInput(DataType.INT));
+        exp = new SimpleExpression(DataType.INT);
+        assertFalse(exp.equals(new SimpleExpression(DataType.STRING)));
+        assertEquals(exp, new SimpleExpression(DataType.INT));
 
         exp = new SimpleExpression().setCreatedOutput(DataType.INT);
         assertFalse(exp.equals(new SimpleExpression().setCreatedOutput(DataType.STRING)));
diff --git a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/StatementTestCase.java b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/StatementTestCase.java
index 27466313fc6..bcec637e5e3 100644
--- a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/StatementTestCase.java
+++ b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/StatementTestCase.java
@@ -76,7 +76,7 @@ public class StatementTestCase {
     @Test
     public void requireThatRequiredInputIsNullIfAnyOutputIsCreatedFirst() {
         assertNull(newStatement(new SimpleExpression().setCreatedOutput(DataType.INT),
-                                new SimpleExpression().setRequiredInput(DataType.INT)).requiredInputType());
+                                new SimpleExpression(DataType.INT)).requiredInputType());
     }
 
     @Test
diff --git a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/VerificationExceptionTestCase.java b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/VerificationExceptionTestCase.java
index a22cc64e115..001f2408576 100644
--- a/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/VerificationExceptionTestCase.java
+++ b/indexinglanguage/src/test/java/com/yahoo/vespa/indexinglanguage/expressions/VerificationExceptionTestCase.java
@@ -14,7 +14,7 @@ public class VerificationExceptionTestCase {
     public void requireThatAccessorsWork() {
         Expression exp = new SimpleExpression();
         VerificationException e = new VerificationException(exp, "foo");
-        assertSame(exp, e.getExpression());
+        assertEquals(exp.toString(), e.getExpression());
         assertEquals("foo", e.getMessage());
         assertTrue(e.toString().contains(exp.toString()));
         assertTrue(e.toString().contains(e.getMessage()));