Make the constraint checker more lenient to fix finding Seq.contains and some variations on foldLeft

engine/src/main/scala/org/virtuslab/inkuire/engine/impl/service/SubstitutionMatchService.scala

@@ -21,7 +21,8 @@ class SubstitutionMatchService(val inkuireDb: InkuireDb) extends BaseMatchServic
         )
         .flatMap { okTypes =>
           State.get[TypingState].map { typingState =>
-            if (okTypes) checkBindings(typingState.variableBindings)
+            if (okTypes)
+              checkBindings(typingState.variableBindings)
             else false
           }
         }
@@ -43,7 +44,7 @@ class SubstitutionMatchService(val inkuireDb: InkuireDb) extends BaseMatchServic
     val actualSignatures = resolveResult.signatures.foldLeft(resolveResult.signatures) {
       case (acc, against) =>
         acc.filter { sgn =>
-          sgn == against || !(sgn.canSubstituteFor(against) && !against.canSubstituteFor(sgn))
+          sgn == against || !sgn.canSubstituteFor(against) || against.canSubstituteFor(sgn)
         }
     }
     val actualSignaturesSize = actualSignatures.headOption.map(_.typesWithVariances.size)
@@ -59,20 +60,26 @@ class SubstitutionMatchService(val inkuireDb: InkuireDb) extends BaseMatchServic
   }
 
   private def checkBindings(bindings: VariableBindings): Boolean = {
-    bindings.bindings.values.forall { types =>
+    val bindingsCorrect = bindings.bindings.values.forall { types =>
       types
         .sliding(2, 1)
         .forall {
           case (a: Type) :: (b: Type) :: Nil =>
-            (ancestryGraph.getAllParentsITIDs(a).contains(b.itid.get) ||
-              ancestryGraph.getAllParentsITIDs(b).contains(a.itid.get)) &&
-            a.params.size == b.params.size &&
-            a.params.map(_.typ).zip(b.params.map(_.typ)).forall {
+            val exactlyEqual = a == b
+            // Disable this check, since it can't handle transitive relations
+            // val relatedToEachOther =
+            //   ancestryGraph.getAllParentsITIDs(a).contains(b.itid.get) ||
+            //     ancestryGraph.getAllParentsITIDs(b).contains(a.itid.get)
+            val sameSize = a.params.size == b.params.size
+            val sameTypes = a.params.map(_.typ).zip(b.params.map(_.typ)).forall {
               case (a: Type, b: Type) => a.itid == b.itid
               case _                  => false
             }
+            exactlyEqual || (sameSize && sameTypes)
           case _ => true
         }
-    } && !TypeVariablesGraph(bindings).hasCyclicDependency
+    }
+    val noCycles = !TypeVariablesGraph(bindings).hasCyclicDependency
+    bindingsCorrect && noCycles
   }
 }

engine/src/main/scala/org/virtuslab/inkuire/engine/impl/service/TopLevelMatchQualityService.scala

@@ -5,11 +5,18 @@ import org.virtuslab.inkuire.engine.impl.model._
 
 class TopLevelMatchQualityService(val db: InkuireDb) extends BaseMatchQualityService with MatchingOps {
 
-  def matchQualityMetric(AnnotatedSignature: AnnotatedSignature, matching: Signature): Int =
-    variancesMatchQualityMetric(
-      AnnotatedSignature.signature.typesWithVariances,
+  def matchQualityMetric(annotatedSignature: AnnotatedSignature, matching: Signature): Int = {
+    val mq = variancesMatchQualityMetric(
+      annotatedSignature.signature.typesWithVariances,
       matching.typesWithVariances
     )
+    val multi = byFunctionNameMetricMultiplier(annotatedSignature.name)
+    (mq * multi).toInt
+  }
+
+  def byFunctionNameMetricMultiplier(name: String): Double =
+    if (List('$', '`').exists(name.contains(_))) 5.0
+    else 1.0 + (name.length / 10.0)
 
   def variancesMatchQualityMetric(typVariances: Seq[Variance], suprVariances: Seq[Variance]): Int =
     typVariances.zip(suprVariances).map { case (v1, v2) => varianceMatchQualityMetric(v1, v2) }.sum

engine/src/test/scala/org/virtuslab/inkuire/engine/BaseEndToEndEngineTest.scala

@@ -23,7 +23,8 @@ trait BaseEndToEndEngineTest {
    */
   def testFunctionFound(signature: String, funName: String)(implicit loc: munit.Location): Unit = {
     test(s"$funName : $signature") {
-      assert(testService().query(signature).exists(_.name == funName))
+      val sigs = testService().query(signature)
+      assert(sigs.exists(_.name == funName))
     }
   }
 }

engine/src/test/scala/org/virtuslab/inkuire/engine/EndToEndEngineTest.scala

@@ -27,7 +27,7 @@ class EndToEndEngineTest extends munit.FunSuite with BaseEndToEndEngineTest {
   testFunctionFound(
     "IArray[Float] => (Float => Boolean) => Boolean",
     "IArray.forall"
-  ) // TODO(kπ) IMHO should be just `forall` (generation bug)
+  )
 
   testFunctionFound("List[A] => B => (B => A => B) => B", "foldLeft")
 
@@ -37,12 +37,15 @@ class EndToEndEngineTest extends munit.FunSuite with BaseEndToEndEngineTest {
 
   testFunctionFound("F[A] => B => ((B, A) => B) => B", "foldLeft")
 
-  // TODO(kπ) this is a bug in constraint checking
-  // testFunctionFound("List[A] => A => (A => A => A) => A", "foldLeft")
+  testFunctionFound("List[A] => A => (A => A => A) => A", "foldLeft")
 
-  // testFunctionFound("List[A] => A => ((A, A) => A) => A", "foldLeft")
+  testFunctionFound("List[A] => A => ((A, A) => A) => A", "foldLeft")
 
-  // testFunctionFound("F[A] => A => (A => A => A) => A", "foldLeft")
+  testFunctionFound("F[A] => A => (A => A => A) => A", "foldLeft")
 
-  // testFunctionFound("F[A] => A => ((A, A) => A) => A", "foldLeft")
+  testFunctionFound("F[A] => A => ((A, A) => A) => A", "foldLeft")
+
+  testFunctionFound("List[A] => A => Boolean", "contains")
+
+  testFunctionFound("Seq[A] => A => Boolean", "contains")
 }