Symetric, transitive and reflexive equality for intersection types

CHANGELOG.md

@@ -17,10 +17,12 @@
 - A constructor or type definition with a single inline argument definition was
   previously allowed to use spaces in the argument definition without
   parentheses. [This is now a syntax error.][11856]
+- Symetric, transitive and reflexive [equality for intersection types][11897]
 
 [11777]: https://github.com/enso-org/enso/pull/11777
 [11600]: https://github.com/enso-org/enso/pull/11600
 [11856]: https://github.com/enso-org/enso/pull/11856
+[11897]: https://github.com/enso-org/enso/pull/11897
 
 # Next Release
 

docs/types/intersection-types.md

@@ -68,7 +68,7 @@ Just as demonstrated at
 https://github.com/enso-org/enso/commit/3d8a0e1b90b20cfdfe5da8d2d3950f644a4b45b8#diff-c6ef852899778b52ce6a11ebf9564d102c273021b212a4848b7678e120776287R23
 -->
 
-## Narrowing Type Check
+### Narrowing Type Check
 
 When an _intersection type_ value is being downcast to _some of the types it
 already represents_, these types become its _visible_ types. Any additional
@@ -160,9 +160,9 @@ Table.join self right:Table -> Table = ...
 
 Such a `Table&Column` value can be returned from the above `Table.join` function
 and while having only `Table` behavior by default, still being able to be
-explicitly casted by the visual environment to `Column`.
+explicitly cast by the visual environment to `Column`.
 
-## Converting Type Check
+### Converting Type Check
 
 When an _intersection type_ is being checked against a type it doesn't
 represent, any of its component types can be used for
@@ -180,3 +180,21 @@ case it looses its `Float` type and `ct:Float` would fail.
 In short: when a [conversion](../syntax/conversions.md) is needed to satisfy a
 type check a new value is created to satisfy just the types requested in the
 check.
+
+## Equality & Hash Code
+
+A value of an intersection type is equal with other value, if all values _it has
+been cast to_ are equal to the other value. E.g. a value of `Complex&Float` is
+equal to some other value only if its `Complex` part and `Float` part are equal
+to the other value. The _hidden_ types of a value (e.g. those that it _can be
+cast to_, if any) aren't considered in the equality check.
+
+The order of types isn't important for equality. E.g. `Complex&Float` value can
+be equal to `Float&Complex` if the individual components (values _it has been
+cast to_) match. As implied by (custom)
+[equality rules](../syntax/functions.md#custom-equality) the `hash` of a value
+of _intersection type_ must thus be a sum of `hash` values of all the values it
+_has been cast to_. As a special case any value wrapped into an _intersection
+type_, but _cast down_ to the original type is `==` and has the same `hash` as
+the original value. E.g. `4.2 : Complex&Float : Float` is `==` and has the same
+`hash` as `4.2` (in spite it _can be cast to_ `Complex`).

engine/runtime-integration-tests/src/test/java/org/enso/interpreter/node/expression/builtin/meta/TypeOfNodeMultiValueTest.java

@@ -88,6 +88,9 @@ private static void registerValue(
     if (!polyValue.isNull()) {
       assertTrue("Type of " + polyValue + " is " + t, t.isMetaObject());
       var rawValue = ContextUtils.unwrapValue(ctx(), polyValue);
+      if (rawValue instanceof EnsoMultiValue) {
+        return;
+      }
       var rawType = ContextUtils.unwrapValue(ctx(), t);
       if (rawType instanceof Type type) {
         var singleMultiValue = EnsoMultiValue.create(new Type[] {type}, 1, new Object[] {rawValue});

engine/runtime-integration-tests/src/test/java/org/enso/interpreter/test/AnyToTest.java

@@ -0,0 +1,120 @@
+package org.enso.interpreter.test;
+
+import static org.junit.Assert.assertTrue;
+
+import java.io.ByteArrayOutputStream;
+import java.nio.charset.StandardCharsets;
+import org.enso.interpreter.runtime.data.EnsoMultiValue;
+import org.enso.interpreter.runtime.data.Type;
+import org.enso.interpreter.runtime.data.text.Text;
+import org.enso.test.utils.ContextUtils;
+import org.graalvm.polyglot.Context;
+import org.graalvm.polyglot.Source;
+import org.junit.AfterClass;
+import org.junit.Before;
+import org.junit.BeforeClass;
+import org.junit.Ignore;
+import org.junit.Test;
+
+public class AnyToTest {
+  private static Context ctx;
+
+  private static final ByteArrayOutputStream out = new ByteArrayOutputStream();
+
+  @BeforeClass
+  public static void initCtx() {
+    ctx = ContextUtils.createDefaultContext(out);
+  }
+
+  @AfterClass
+  public static void disposeCtx() {
+    ctx.close();
+    ctx = null;
+  }
+
+  @Before
+  public void resetOutput() {
+    out.reset();
+  }
+
+  private String getStdOut() {
+    return out.toString(StandardCharsets.UTF_8);
+  }
+
+  @Test
+  public void multiValueToInteger() throws Exception {
+    var ensoCtx = ContextUtils.leakContext(ctx);
+    var types =
+        new Type[] {ensoCtx.getBuiltins().number().getInteger(), ensoCtx.getBuiltins().text()};
+    var code =
+        """
+    from Standard.Base import all
+
+    private eq a b = a == b
+
+    conv style v = case style of
+        0 -> v.to Integer
+        1 -> v:Integer
+        99 -> eq
+
+    """;
+    var conv =
+        ContextUtils.evalModule(ctx, Source.newBuilder("enso", code, "conv.enso").build(), "conv");
+    var both = EnsoMultiValue.create(types, types.length, new Object[] {2L, Text.create("Two")});
+    var eq =
+        ContextUtils.executeInContext(
+            ctx,
+            () -> {
+              var bothValue = ctx.asValue(both);
+              var asIntegerTo = conv.execute(0, bothValue);
+              var asIntegerCast = conv.execute(1, bothValue);
+              var equals = conv.execute(99, null);
+              return equals.execute(asIntegerTo, asIntegerCast);
+            });
+    assertTrue("Any.to and : give the same result", eq.asBoolean());
+  }
+
+  @Test
+  @Ignore
+  public void multiValueToText() throws Exception {
+    multiValueToText(2);
+  }
+
+  @Test
+  @Ignore
+  public void multiValueToTextHidden() throws Exception {
+    multiValueToText(1);
+  }
+
+  private void multiValueToText(int dispatchLength) throws Exception {
+    var ensoCtx = ContextUtils.leakContext(ctx);
+    var types =
+        new Type[] {ensoCtx.getBuiltins().number().getInteger(), ensoCtx.getBuiltins().text()};
+    var code =
+        """
+    from Standard.Base import all
+
+    private eq a b = a == b
+
+    conv style:Integer v = case style of
+        2 -> v.to Text
+        3 -> v:Text
+        99 -> eq
+
+    """;
+    var conv =
+        ContextUtils.evalModule(ctx, Source.newBuilder("enso", code, "conv.enso").build(), "conv");
+    var both = EnsoMultiValue.create(types, dispatchLength, new Object[] {2L, Text.create("Two")});
+    var eq =
+        ContextUtils.executeInContext(
+            ctx,
+            () -> {
+              var bothValue = ctx.asValue(both);
+              var asIntegerCast = conv.execute(3, bothValue);
+              var asIntegerTo = conv.execute(2, bothValue);
+              var equals = conv.execute(99, null);
+              return equals.execute(asIntegerTo, asIntegerCast);
+            });
+    assertTrue("Any.to and : give the same result", eq.asBoolean());
+  }
+}

engine/runtime-integration-tests/src/test/java/org/enso/interpreter/test/EnsoMultiValueInteropTest.java

@@ -57,7 +57,13 @@ private static void registerValue(
       var rawT2 = ContextUtils.unwrapValue(ctx(), t2);
       if (rawT1 instanceof Type typ1 && rawT2 instanceof Type typ2) {
         var r1 = ContextUtils.unwrapValue(ctx, v1);
+        if (r1 instanceof EnsoMultiValue) {
+          return;
+        }
         var r2 = ContextUtils.unwrapValue(ctx, v2);
+        if (r2 instanceof EnsoMultiValue) {
+          return;
+        }
         var both = EnsoMultiValue.create(new Type[] {typ1, typ2}, 2, new Object[] {r1, r2});
         data.add(new Object[] {both});
       }

engine/runtime-integration-tests/src/test/java/org/enso/interpreter/test/EqualsMultiValueTest.java

@@ -111,15 +111,24 @@ public void testEqualityIntegerAndMultiValueWithBoth() {
           var intType = builtins.number().getInteger();
           var textText = builtins.text();
           var hi = Text.create("Hi");
-          var fourExtraText =
+          var textFour =
               EnsoMultiValue.create(new Type[] {textText, intType}, 2, new Object[] {hi, 4L});
-
-          assertTrue("4 == 4t", equalityCheck(4L, fourExtraText));
-          assertFalse("5 != 4t", equalityCheck(5L, fourExtraText));
-          assertTrue("4t == 4", equalityCheck(fourExtraText, 4L));
-          assertFalse("4t != 5", equalityCheck(fourExtraText, 5L));
-          assertTrue("4t == 'Hi'", equalityCheck(fourExtraText, hi));
-          assertTrue("'Hi' == 4t", equalityCheck(hi, fourExtraText));
+          var textFive =
+              EnsoMultiValue.create(new Type[] {textText, intType}, 2, new Object[] {hi, 5L});
+          var fourText =
+              EnsoMultiValue.create(new Type[] {intType, textText}, 2, new Object[] {4L, hi});
+
+          assertFalse("4 != t", equalityCheck(4L, hi));
+          assertFalse("4 != 4t", equalityCheck(4L, textFour));
+          assertFalse("5 != 4t", equalityCheck(5L, textFour));
+          assertFalse("5t != 4t", equalityCheck(textFive, textFour));
+          assertFalse("4t != 4", equalityCheck(textFour, 4L));
+          assertFalse("4t != 5", equalityCheck(textFour, 5L));
+          assertFalse("4t != 'Hi'", equalityCheck(textFour, hi));
+          assertFalse("'Hi' != 4t", equalityCheck(hi, textFour));
+
+          assertTrue("t4 == 4t", equalityCheck(textFour, fourText));
+          assertTrue("4t == t4", equalityCheck(fourText, textFour));
 
           return null;
         });
@@ -137,9 +146,9 @@ public void testEqualityIntegerAndMultiValueWithIntText() {
               EnsoMultiValue.create(
                   new Type[] {intType, textText}, 2, new Object[] {4L, Text.create("Hi")});
 
-          assertTrue("4 == 4t", equalityCheck(4L, fourExtraText));
+          assertFalse("4 != 4t", equalityCheck(4L, fourExtraText));
           assertFalse("5 != 4t", equalityCheck(5L, fourExtraText));
-          assertTrue("4t == 4", equalityCheck(fourExtraText, 4L));
+          assertFalse("4t != 4", equalityCheck(fourExtraText, 4L));
           assertFalse("4t != 5", equalityCheck(fourExtraText, 5L));
 
           return null;

engine/runtime-integration-tests/src/test/java/org/enso/interpreter/test/ValuesGenerator.java

@@ -25,6 +25,11 @@
 import java.util.TimeZone;
 import org.enso.common.MethodNames;
 import org.enso.common.MethodNames.Module;
+import org.enso.interpreter.node.expression.foreign.HostValueToEnsoNode;
+import org.enso.interpreter.runtime.data.EnsoMultiValue;
+import org.enso.interpreter.runtime.data.EnsoObject;
+import org.enso.interpreter.runtime.data.Type;
+import org.enso.test.utils.ContextUtils;
 import org.graalvm.polyglot.Context;
 import org.graalvm.polyglot.PolyglotException;
 import org.graalvm.polyglot.Value;
@@ -865,6 +870,41 @@ public List<Value> problemBehaviors() {
     return collect;
   }
 
+  public List<Value> numbersMultiText() {
+    var leak = ContextUtils.leakContext(ctx);
+    var numberTextTypes =
+        new Type[] {
+          leak.getBuiltins().number().getInteger(), leak.getBuiltins().text(),
+        };
+    var textNumberTypes =
+        new Type[] {
+          leak.getBuiltins().text(), leak.getBuiltins().number().getInteger(),
+        };
+    var collect = new ArrayList<Value>();
+    var toEnso = HostValueToEnsoNode.getUncached();
+    for (var n : numbers()) {
+      for (var t : textual()) {
+        var rawN = toEnso.execute(ContextUtils.unwrapValue(ctx, n));
+        var rawT = ContextUtils.unwrapValue(ctx, t);
+        if (!(rawT instanceof EnsoObject)) {
+          continue;
+        }
+        addMultiToCollect(collect, numberTextTypes, 2, rawN, rawT);
+        addMultiToCollect(collect, numberTextTypes, 1, rawN, rawT);
+        addMultiToCollect(collect, textNumberTypes, 2, rawT, rawN);
+        addMultiToCollect(collect, textNumberTypes, 1, rawT, rawN);
+      }
+    }
+    return collect;
+  }
+
+  private void addMultiToCollect(
+      List<Value> collect, Type[] types, int dispatchTypes, Object... values) {
+    var raw = EnsoMultiValue.create(types, dispatchTypes, values);
+    var wrap = ctx.asValue(raw);
+    collect.add(wrap);
+  }
+
   public List<Value> noWrap() {
     var collect = new ArrayList<Value>();
     if (languages.contains(Language.ENSO)) {

engine/runtime-integration-tests/src/test/java/org/enso/interpreter/test/hash/HashCodeTest.java

@@ -73,6 +73,7 @@ private static Object[] fetchAllUnwrappedValues() {
     values.addAll(valGenerator.numbers());
     values.addAll(valGenerator.booleans());
     values.addAll(valGenerator.textual());
+    values.addAll(valGenerator.numbersMultiText());
     values.addAll(valGenerator.arrayLike());
     values.addAll(valGenerator.vectors());
     values.addAll(valGenerator.maps());