Enforce conversion method return type & redefine Comparable

distribution/lib/Standard/Base/0.0.0-dev/src/Any.enso

@@ -13,6 +13,7 @@ from project.Data.Boolean import Boolean, False, True
 from project.Data.Ordering import all
 from project.Data.Range.Extensions import all
 from project.Function import const
+from project.Internal.Ordering_Helpers import assert_same_comparators
 
 ## Any is the universal top-type, with all other types being subsumed by it.
 
@@ -195,8 +196,8 @@ type Any
                  a > 147
     > : Any -> Boolean ! Incomparable_Values
     > self that =
-        assert_same_comparators self that <|
-            case (Comparable.from self).compare self that of
+        assert_same_comparators self that comparator->
+            case comparator.compare self that of
                 Ordering.Greater -> True
                 Nothing -> Error.throw (Incomparable_Values.Error self that)
                 _ -> False
@@ -225,8 +226,8 @@ type Any
                  a >= 147
     >= : Any -> Boolean ! Incomparable_Values
     >= self that =
-        assert_same_comparators self that <|
-            case (Comparable.from self).compare self that of
+        assert_same_comparators self that comparator->
+            case comparator.compare self that of
                 Ordering.Equal -> True
                 Ordering.Greater -> True
                 Nothing -> Error.throw (Incomparable_Values.Error self that)
@@ -255,8 +256,8 @@ type Any
                  a < 147
     < : Any -> Boolean ! Incomparable_Values
     < self that =
-        assert_same_comparators self that <|
-            case (Comparable.from self).compare self that of
+        assert_same_comparators self that comparator->
+            case comparator.compare self that of
                 Ordering.Less -> True
                 Nothing -> Error.throw (Incomparable_Values.Error self that)
                 _ -> False
@@ -287,8 +288,8 @@ type Any
                  a < 147
     <= : Any -> Boolean ! Incomparable_Values
     <= self that =
-        assert_same_comparators self that <|
-            case (Comparable.from self).compare self that of
+        assert_same_comparators self that comparator->
+            case comparator.compare self that of
                 Ordering.Equal -> True
                 Ordering.Less -> True
                 Nothing -> Error.throw (Incomparable_Values.Error self that)
@@ -505,13 +506,3 @@ type Any
         _ = warning_type
         self
 
-## PRIVATE
-   Checks if the comparators for the given objects are both of the same type. If so,
-   proceeds with the given action, and if not, throws `Incomparable_Values` error.
-assert_same_comparators : Any -> Any -> (Any -> Any) -> Any ! Incomparable_Values
-assert_same_comparators this that ~action =
-    comp_this = Comparable.from this
-    comp_that = Comparable.from that
-    case Meta.is_same_object comp_this comp_that of
-        True -> action
-        False -> Error.throw (Incomparable_Values.Error this that)

distribution/lib/Standard/Base/0.0.0-dev/src/Data/Decimal.enso

@@ -1059,10 +1059,10 @@ handle_unsupported_argument_types ~action =
         Error.throw (Arithmetic_Error.Error "Exponent out of range 0..999999999 (inclusive)")
 
 ## PRIVATE
-Comparable.from (_ : Decimal) = Decimal_Comparator
+Comparable.from (that : Decimal) = Comparable.new that Decimal_Comparator
 
 ## PRIVATE
-Comparable.from (_ : Number) = Decimal_Comparator
+Comparable.from (that : Number) = Comparable.new that Decimal_Comparator
 
 ## PRIVATE
 Decimal.from (that : Text) = Decimal.from_string that

distribution/lib/Standard/Base/0.0.0-dev/src/Data/Json.enso

@@ -367,12 +367,12 @@ type JS_Object_Comparator
     hash obj =
         values_hashes = obj.field_names.map field_name->
             val = obj.get field_name
-            Comparable.from val . hash val
+            Comparable.from val . hash
         # Return sum, as we don't care about ordering of field names
         values_hashes.fold 0 (+)
 
 ## PRIVATE
-Comparable.from (_:JS_Object) = JS_Object_Comparator
+Comparable.from (that:JS_Object) = Comparable.new that JS_Object_Comparator
 
 ## PRIVATE
    Render the JS_Object to Text with truncated depth.

distribution/lib/Standard/Base/0.0.0-dev/src/Data/Numbers.enso

@@ -15,6 +15,7 @@ import project.Panic.Panic
 from project.Data.Boolean import Boolean, False, True
 from project.Internal.Number_Builtins import all
 from project.Widget_Helpers import make_number_format_selector
+from project.Internal.Ordering_Helpers import Positive_Integer_Comparator
 
 polyglot java import java.lang.Double
 polyglot java import java.lang.Long
@@ -1288,13 +1289,4 @@ Positive_Integer.from (that : Integer) = Positive_Integer.new that
 Integer.from (that : Positive_Integer) = that.integer
 
 ## PRIVATE
-type Positive_Integer_Comparator
-    ## PRIVATE
-    compare x y =
-        Comparable.from x.integer . compare x.integer y.integer
-
-    ## PRIVATE
-    hash x = Comparable.from x.integer . hash x.integer
-
-## PRIVATE
-Comparable.from (_:Positive_Integer) = Positive_Integer_Comparator
+Comparable.from (that:Positive_Integer) = Comparable.new that Positive_Integer_Comparator

distribution/lib/Standard/Base/0.0.0-dev/src/Data/Ordering.enso

@@ -11,6 +11,7 @@ import project.Meta.Atom
 import project.Nothing.Nothing
 import project.Panic.Panic
 from project.Data.Boolean import Boolean, False, True
+from project.Internal.Ordering_Helpers import all
 
 ## Provides custom ordering, equality check and hash code for types that need it.
 
@@ -109,6 +110,26 @@ from project.Data.Boolean import Boolean, False, True
        the custom comparator whenever equality or hash code is needed.
 @Builtin_Type
 type Comparable
+    private By value:Any comparator:Any
+
+    ##
+       Creates new comparable instance for given `value` and
+       a `comparator` with two static methods what work on the
+       type `T` of the provided `value`:
+
+       ```
+       type Comparator T
+           compare : T -> T -> (Ordering|Nothing)
+           hash : T -> Integer
+       ```
+    new value:Any comparator:Any -> Comparable = Comparable.By value comparator
+
+    compare self that:Comparable = case Meta.is_same_object self.comparator that.comparator of
+        True -> self.comparator.compare self.value that.value
+        False -> Error.throw (Incomparable_Values.Error self that)
+
+    hash self -> Integer = self.comparator.hash self.value
+
     ## PRIVATE
        Called as a callback from internal engine code for an atom with a custom
        comparator. It is assumed that the given atom has a custom comparator, that is
@@ -147,7 +168,7 @@ type Default_Comparator
     hash x = Comparable.hash_builtin x
 
 ## PRIVATE
-Comparable.from (_:Any) = Default_Comparator
+Comparable.from (that:Any) = Comparable.new that Default_Comparator
 
 ## Types representing the ordering of values.
 @Builtin_Type
@@ -213,12 +234,4 @@ type Ordering
         if sign > 0 then Ordering.Greater else Ordering.Less
 
 ## PRIVATE
-type Ordering_Comparator
-    ## PRIVATE
-    compare x y = (Comparable.from x.to_sign).compare x.to_sign y.to_sign
-
-    ## PRIVATE
-    hash x = x.to_sign
-
-## PRIVATE
-Comparable.from (_:Ordering) = Ordering_Comparator
+Comparable.from (that:Ordering) = Comparable.new that Ordering_Comparator

distribution/lib/Standard/Base/0.0.0-dev/src/Data/Time/Day_Of_Week.enso

@@ -78,7 +78,7 @@ type Day_Of_Week_Comparator
     hash x = x.to_integer
 
 ## PRIVATE
-Comparable.from (_:Day_Of_Week) = Day_Of_Week_Comparator
+Comparable.from (that:Day_Of_Week) = Comparable.new that Day_Of_Week_Comparator
 
 ## PRIVATE
    Convert from an integer to a Day_Of_Week

distribution/lib/Standard/Base/0.0.0-dev/src/Internal/Array_Like_Helpers.enso

@@ -150,8 +150,8 @@ check_start_valid start length function =
 
 sort vector order on by on_problems:Problem_Behavior =
     comps = case on == Nothing of
-        True -> vector.map it-> Comparable.from it
-        False -> vector.map it-> Comparable.from (on it)
+        True -> vector.map it-> Comparable.from it . comparator
+        False -> vector.map it-> Comparable.from (on it) . comparator
     compare_funcs = comps.map (it-> it.compare)
     vector.sort_builtin order.to_sign comps compare_funcs by on (on_problems_to_number on_problems)
 

distribution/lib/Standard/Base/0.0.0-dev/src/Internal/Ordering_Helpers.enso

@@ -0,0 +1,36 @@
+private
+
+import project.Any.Any
+from project.Data.Boolean import Boolean, False, True
+from project.Data.Ordering import all
+import project.Errors.Common.Incomparable_Values
+import project.Error.Error
+import project.Meta
+
+## PRIVATE
+   Checks if the comparators for the given objects are both of the same type. If so,
+   proceeds with the given action, and if not, throws `Incomparable_Values` error.
+assert_same_comparators : Any -> Any -> (Any -> Any) -> Any ! Incomparable_Values
+assert_same_comparators this that ~action =
+    comp_this = Comparable.from this
+    comp_that = Comparable.from that
+    case Meta.is_same_object comp_this.comparator comp_that.comparator of
+        True -> action comp_this.comparator
+        False -> Error.throw (Incomparable_Values.Error this that)
+
+## PRIVATE
+type Positive_Integer_Comparator
+    ## PRIVATE
+    compare x y =
+        Comparable.from x.integer . compare y.integer
+
+    ## PRIVATE
+    hash x = Comparable.from x.integer . hash
+
+## PRIVATE
+type Ordering_Comparator
+    ## PRIVATE
+    compare x y = (Comparable.from x.to_sign).compare y.to_sign
+
+    ## PRIVATE
+    hash x = x.to_sign

distribution/lib/Standard/Base/0.0.0-dev/src/Network/HTTP/Header.enso

@@ -228,4 +228,4 @@ type Header_Comparator
         Comparable.from key . hash key
 
 ## PRIVATE
-Comparable.from (_:Header) = Header_Comparator
+Comparable.from (that:Header) = Comparable.new that Header_Comparator

distribution/lib/Standard/Base/0.0.0-dev/src/Network/URI.enso

@@ -336,7 +336,7 @@ type URI_Comparator
         Comparable.from txt . hash txt
 
 ## PRIVATE
-Comparable.from (_:URI) = URI_Comparator
+Comparable.from (that:URI) = Comparable.new that URI_Comparator
 
 ## PRIVATE
 type Invalid_Query_String

distribution/lib/Standard/Database/0.0.0-dev/src/Internal/IR/From_Spec.enso

@@ -110,4 +110,4 @@ type From_Spec_Comparator
         _ -> Default_Comparator.hash x
 
 ## PRIVATE
-Comparable.from (_ : From_Spec) = From_Spec_Comparator
+Comparable.from (that : From_Spec) = Comparable.new that From_Spec_Comparator

distribution/lib/Standard/Image/0.0.0-dev/src/Image.enso

@@ -489,4 +489,4 @@ type Image_Comparator
     hash x = x.opencv_mat.hashCode
 
 ## PRIVATE
-Comparable.from (_:Image) = Image_Comparator
+Comparable.from (that:Image) = Comparable.new that Image_Comparator

distribution/lib/Standard/Image/0.0.0-dev/src/Matrix.enso

@@ -450,4 +450,4 @@ type Matrix_Comparator
     hash x = x.opencv_mat.hashCode
 
 ## PRIVATE
-Comparable.from (_:Matrix) = Matrix_Comparator
+Comparable.from (that:Matrix) = Comparable.new that Matrix_Comparator

distribution/lib/Standard/Table/0.0.0-dev/src/Internal/Multi_Value_Key.enso

@@ -52,7 +52,7 @@ type Unordered_Multi_Value_Key_Comparator
     hash x = x.hash_code
 
 ## PRIVATE
-Comparable.from (_:Unordered_Multi_Value_Key) = Unordered_Multi_Value_Key_Comparator
+Comparable.from (that:Unordered_Multi_Value_Key) = Comparable.new that Unordered_Multi_Value_Key_Comparator
 
 ## PRIVATE
    An Enso implementation mirroring `OrderedMultiValueKey` from the Java
@@ -94,4 +94,4 @@ type Ordered_Multi_Value_Key_Comparator
         Error.throw (Illegal_State.new "Ordered_Multi_Value_Key is not intended for usage in unordered collections.")
 
 ## PRIVATE
-Comparable.from (_:Ordered_Multi_Value_Key) = Ordered_Multi_Value_Key_Comparator
+Comparable.from (that:Ordered_Multi_Value_Key) = Comparable.new that Ordered_Multi_Value_Key_Comparator

distribution/lib/Standard/Table/0.0.0-dev/src/Value_Type.enso

@@ -47,7 +47,7 @@ type Bits_Comparator
     hash x = Comparable.from x.to_integer . hash x.to_integer
 
 ## PRIVATE
-Comparable.from (_:Bits) = Bits_Comparator
+Comparable.from (that:Bits) = Comparable.new that Bits_Comparator
 
 ## Represents the different possible types of values within Table columns.
 
@@ -487,10 +487,10 @@ type Value_Type
 type Auto
 
 ## The type representing the column type being explicitly selected by the user.
-   Arguments: 
-   - type: The type of columns to select. 
+   Arguments:
+   - type: The type of columns to select.
 type By_Type
     ## The type representing the column type being explicitly selected by the user.
-       Arguments: 
+       Arguments:
        - type: The type of columns to select.
     By_Type type:Value_Type

distribution/lib/Standard/Test/0.0.0-dev/src/Group.enso

@@ -68,4 +68,4 @@ type Group_Comparator
         text_comp = Comparable.from g.name
         text_comp.hash g.name
 
-Comparable.from (_:Group) = Group_Comparator
+Comparable.from (that:Group) = Comparable.new that Group_Comparator

engine/runtime-integration-tests/src/test/java/org/enso/compiler/ExecCompilerTest.java

@@ -484,4 +484,29 @@ public void illegalPrivateConversion() throws Exception {
     runMethod.execute(0);
     assertThat(out.toString(), containsString(expectedErrMsg));
   }
+
+  @Test
+  public void resultOfConversionIsTypeChecked() throws Exception {
+    var code =
+        """
+        type First_Type
+        type Other_Type
+
+        First_Type.from (that:Other_Type) = 42
+        run value -> First_Type = Other_Type
+        """;
+    var module = ctx.eval(LanguageInfo.ID, code);
+    var runMethod = module.invokeMember(Module.EVAL_EXPRESSION, "run");
+    try {
+      var r = runMethod.execute(0);
+      fail("We don't expect any result, but exception: " + r);
+    } catch (PolyglotException ex) {
+      assertThat(
+          ex.getMessage().toLowerCase(),
+          AllOf.allOf(containsString("type"), containsString("error")));
+      var typeError = ex.getGuestObject();
+      assertEquals("Expected type", "First_Type", typeError.getMember("expected").toString());
+      assertEquals("Got wrong value", 42, typeError.getMember("actual").asInt());
+    }
+  }
 }

engine/runtime/src/main/java/org/enso/interpreter/node/expression/builtin/meta/EqualsNode.java

@@ -20,6 +20,8 @@
 import org.enso.interpreter.runtime.callable.argument.CallArgumentInfo;
 import org.enso.interpreter.runtime.callable.function.Function;
 import org.enso.interpreter.runtime.data.Type;
+import org.enso.interpreter.runtime.data.atom.Atom;
+import org.enso.interpreter.runtime.data.atom.StructsLibrary;
 import org.enso.interpreter.runtime.error.PanicException;
 import org.enso.interpreter.runtime.library.dispatch.TypeOfNode;
 import org.enso.interpreter.runtime.scope.ModuleScope;
@@ -140,8 +142,15 @@ private static Object convertor(EnsoContext ctx, Function convFn, Object value)
           InvokeFunctionNode.build(
               argSchema, DefaultsExecutionMode.EXECUTE, ArgumentsExecutionMode.EXECUTE);
       var state = State.create(ctx);
-      return node.execute(
-          convFn, null, state, new Object[] {ctx.getBuiltins().comparable(), value});
+      var by =
+          node.execute(convFn, null, state, new Object[] {ctx.getBuiltins().comparable(), value});
+      if (by instanceof Atom atom
+          && atom.getConstructor() == ctx.getBuiltins().comparable().getBy()) {
+        var structs = StructsLibrary.getUncached();
+        return structs.getField(atom, 1);
+      } else {
+        return null;
+      }
     }
 
     /**
@@ -175,14 +184,14 @@ private static boolean findConversionImpl(
           UnresolvedConversion.build(selfScope).resolveFor(ctx, comparableType, thatType);
       var betweenBoth = UnresolvedConversion.build(selfScope).resolveFor(ctx, selfType, thatType);
 
-      if (isDefinedIn(selfScope, fromSelfType)
-          && isDefinedIn(selfScope, fromThatType)
-          && convertor(ctx, fromSelfType, self) == convertor(ctx, fromThatType, that)
-          && betweenBoth != null) {
-        return true;
-      } else {
-        return false;
+      if (isDefinedIn(selfScope, fromSelfType) && isDefinedIn(selfScope, fromThatType)) {
+        var c1 = convertor(ctx, fromSelfType, self);
+        var c2 = convertor(ctx, fromThatType, that);
+        if (c1 == c2 && c1 != null && betweenBoth != null) {
+          return true;
+        }
       }
+      return false;
     }
 
     @Specialization(