reporting ignored overloaded specs

Summary:
- when a function literal is used (like `fun foo/1`) and the corresponding function has overloaded specs, we elaborate the type of such expression as `dynamic() -> dynamic()`, since overloaded specs are not the part of "language of types"
- adding an option to introspect such approximations

Reviewed By: VLanvin

Differential Revision: D62641981

fbshipit-source-id: 1d7d3c3452640510a4b49acdc99f5d5768ce7bd8

eqwalizer/src/main/resources/application.conf

@@ -14,4 +14,6 @@ eqwalizer {
     overloaded_spec_dynamic_result = ${?EQWALIZER_OVERLOADED_SPEC_DYNAMIC_RESULT}
     custom_maps_merge = false
     custom_maps_merge = ${?EQWALIZER_CUSTOM_MAPS_MERGE}
+    ignored_overloaded_spec = false
+    ignored_overloaded_spec = ${?EQWALIZER_IGNORED_OVERLOADED_SPEC}
 }

eqwalizer/src/main/scala/com/whatsapp/eqwalizer/package.scala

@@ -37,6 +37,7 @@ package object eqwalizer {
       customMapsMerge: Boolean,
       mode: Mode.Mode,
       errorDepth: Int,
+      ignoredOverloadedSpec: Boolean,
   )
 
   lazy val config: Config = {
@@ -52,6 +53,7 @@ package object eqwalizer {
       customMapsMerge = config.getBoolean("custom_maps_merge"),
       mode,
       errorDepth = config.getInt("error_depth"),
+      ignoredOverloadedSpec = config.getBoolean("ignored_overloaded_spec"),
     )
   }
 }

eqwalizer/src/main/scala/com/whatsapp/eqwalizer/tc/Check.scala

@@ -260,13 +260,20 @@ final class Check(pipelineContext: PipelineContext) {
           }
           env2
         case LocalFun(id) =>
-          val ft = util.getFunType(module, id)
+          val fqn = util.globalFunId(module, id)
+          if (pipelineCtx.ignoredOverloadedSpec && util.getOverloadedSpec(fqn).isDefined) {
+            diagnosticsInfo.add(IgnoredOverloadedSpec(expr.pos))
+          }
+          val ft = util.getFunType(fqn)
           val ft1 = freshen(ft)
           if (!subtype.subType(ft1, resTy))
             diagnosticsInfo.add(ExpectedSubtype(expr.pos, expr, expected = resTy, got = ft1))
           env
         case RemoteFun(fqn) =>
           val ft = util.getFunType(fqn)
+          if (pipelineCtx.ignoredOverloadedSpec && util.getOverloadedSpec(fqn).isDefined) {
+            diagnosticsInfo.add(IgnoredOverloadedSpec(expr.pos))
+          }
           val ft1 = freshen(ft)
           if (!subtype.subType(ft1, resTy))
             diagnosticsInfo.add(ExpectedSubtype(expr.pos, expr, expected = resTy, got = ft1))

eqwalizer/src/main/scala/com/whatsapp/eqwalizer/tc/Elab.scala

@@ -227,10 +227,17 @@ final class Elab(pipelineContext: PipelineContext) {
           (resTy, env1)
         }
       case LocalFun(id) =>
-        val ft = util.getFunType(module, id)
+        val fqn = util.globalFunId(module, id)
+        if (pipelineCtx.ignoredOverloadedSpec && util.getOverloadedSpec(fqn).isDefined) {
+          diagnosticsInfo.add(IgnoredOverloadedSpec(expr.pos))
+        }
+        val ft = util.getFunType(fqn)
         (check.freshen(ft), env)
       case RemoteFun(fqn) =>
         val ft = util.getFunType(fqn)
+        if (pipelineCtx.ignoredOverloadedSpec && util.getOverloadedSpec(fqn).isDefined) {
+          diagnosticsInfo.add(IgnoredOverloadedSpec(expr.pos))
+        }
         (check.freshen(ft), env)
       case lambda @ Lambda(clauses) =>
         val arity = clauses.head.pats.length

eqwalizer/src/main/scala/com/whatsapp/eqwalizer/tc/TcDiagnostics.scala

@@ -46,7 +46,7 @@ object TcDiagnostics {
   }
   case class IgnoredOverloadedSpec(pos: Pos) extends TypeError {
     override val msg: String = s"dynamic() -> dynamic() is used"
-    def errorName = "not_enough_info_to_branch"
+    def errorName = "ignored_overloaded_spec"
     override def erroneousExpr: Option[Expr] = None
   }
   case class LambdaArityMismatch(pos: Pos, expr: Expr, lambdaArity: Int, argsArity: Int) extends TypeError {

eqwalizer/src/main/scala/com/whatsapp/eqwalizer/tc/package.scala

@@ -69,5 +69,6 @@ package object tc {
     val clauseCoverage: Boolean = config.clauseCoverage
     val overloadedSpecDynamicResult: Boolean = config.overloadedSpecDynamicResult
     val customMapsMerge: Boolean = config.customMapsMerge
+    val ignoredOverloadedSpec: Boolean = config.ignoredOverloadedSpec
   }
 }