Merge pull request scalacenter#390 from sjrd/default-params

Add methods to detect parameters with default values.

Author: sjrd

tasty-query/shared/src/main/scala/tastyquery/Flags.scala

@@ -55,6 +55,7 @@ private[tastyquery] object Flags:
   val Extension: Flag = newFlag("Extension")
   val Final: Flag = newFlag("Final")
   val Given: Flag = newFlag("Given")
+  val HasDefault: Flag = newFlag("HasDefault")
   val Implicit: Flag = newFlag("Implicit")
   val Infix: Flag = newFlag("Infix")
   val Inline: Flag = newFlag("Inline")

tasty-query/shared/src/main/scala/tastyquery/Symbols.scala

@@ -583,6 +583,17 @@ object Symbols {
     /** Is this symbol an exporter generated by an `export` statement? */
     final def isExport: Boolean = flags.is(Exported)
 
+    /** Is this symbol a method with at least one parameter with a default value? */
+    final def hasParamWithDefault: Boolean =
+      paramSymss.exists {
+        case Left(termParams) => termParams.exists(_.isParamWithDefault)
+        case Right(value)     => false
+      }
+    end hasParamWithDefault
+
+    /** Is this symbol a method parameter with a default value? */
+    final def isParamWithDefault: Boolean = flags.isAllOf(HasDefault)
+
     /** Get the module class of this module value definition, if it exists:
       * - for `object val C` => `object class C[$]`
       */

tasty-query/shared/src/main/scala/tastyquery/reader/pickles/PickleReader.scala

@@ -487,7 +487,7 @@ private[pickles] class PickleReader {
     if pickleFlags.isStable then flags |= StableRealizable
     if pickleFlags.isStatic then flags |= Static
     if pickleFlags.isCaseAccessor then flags |= CaseAccessor
-    // if pickleFlags.hasDefault then flags |= HasDefault
+    if pickleFlags.hasDefault then flags |= HasDefault
     if pickleFlags.isTrait then flags |= Trait
     // if pickleFlags.isBridge then flags |= Bridge
     if pickleFlags.isAccessor then flags |= Accessor

tasty-query/shared/src/main/scala/tastyquery/reader/tasties/TreeUnpickler.scala

@@ -312,7 +312,7 @@ private[tasties] class TreeUnpickler private (
         case CASEaccessor  => addFlag(CaseAccessor)
         case COVARIANT     => addFlag(Covariant)
         case CONTRAVARIANT => addFlag(Contravariant)
-        case HASDEFAULT    => ignoreFlag()
+        case HASDEFAULT    => addFlag(HasDefault)
         case STABLE        => addFlag(StableRealizable)
         case EXTENSION     => addFlag(Extension)
         case GIVEN         => addFlag(Given)

tasty-query/shared/src/test/scala/tastyquery/TypeSuite.scala

@@ -1051,18 +1051,45 @@ class TypeSuite extends UnrestrictedUnpicklingSuite {
         throw AssertionError(s"unexpected type $tpe")
   }
 
-  testWithContext("scala-2-default-params") {
+  testWithContext("default-params") {
+    extension (sym: TermSymbol) def paramCount: Int = sym.declaredType.asInstanceOf[MethodType].paramNames.size
+
     val DefaultParamsClass = ctx.findTopLevelClass("simple_trees.DefaultParams")
     assert(clue(DefaultParamsClass.getNonOverloadedDecl(DefaultGetterName(termName("foo"), 0))).isEmpty)
     DefaultParamsClass.findNonOverloadedDecl(DefaultGetterName(termName("foo"), 1))
     DefaultParamsClass.findNonOverloadedDecl(DefaultGetterName(termName("foo"), 2))
     assert(clue(DefaultParamsClass.getNonOverloadedDecl(DefaultGetterName(termName("foo"), 3))).isEmpty)
 
+    val fooOverloads = DefaultParamsClass.findAllOverloadedDecls(termName("foo"))
+
+    val fooWithDefaults = fooOverloads.find(_.paramCount == 3).get
+    assert(clue(fooWithDefaults.hasParamWithDefault) && !clue(fooWithDefaults.isParamWithDefault))
+    val List(Left(fooWithDefaultsParams)) = fooWithDefaults.paramSymss: @unchecked
+    assert(clue(fooWithDefaultsParams.map(_.isParamWithDefault)) == List(false, true, true))
+    assert(clue(fooWithDefaultsParams.map(_.hasParamWithDefault)).forall(_ == false))
+
+    for fooOverload <- fooOverloads if fooOverload ne fooWithDefaults do
+      assert(!clue(fooOverload.hasParamWithDefault) && !clue(fooOverload.isParamWithDefault))
+      val List(Left(params)) = fooOverload.paramSymss: @unchecked
+      assert(clue(params.map(_.isParamWithDefault)).forall(_ == false))
+      assert(clue(params.map(_.hasParamWithDefault)).forall(_ == false))
+  }
+
+  testWithContext("default-params-scala-2") {
     val IteratorClass = ctx.findTopLevelClass("scala.collection.Iterator")
     assert(clue(IteratorClass.getNonOverloadedDecl(DefaultGetterName(termName("indexWhere"), 0))).isEmpty)
     IteratorClass.findNonOverloadedDecl(DefaultGetterName(termName("indexWhere"), 1))
     assert(clue(IteratorClass.getNonOverloadedDecl(DefaultGetterName(termName("indexWhere"), 2))).isEmpty)
 
+    locally {
+      val indexWhere = IteratorClass.findNonOverloadedDecl(termName("indexWhere"))
+      assert(clue(indexWhere.hasParamWithDefault) && !clue(indexWhere.isParamWithDefault))
+
+      val List(Left(List(p, from))) = indexWhere.paramSymss: @unchecked
+      assert(!clue(p.hasParamWithDefault) && !clue(p.isParamWithDefault))
+      assert(!clue(from.hasParamWithDefault) && clue(from.isParamWithDefault))
+    }
+
     val ArrayDequeModClass = ctx.findTopLevelModuleClass("scala.collection.mutable.ArrayDeque")
     ArrayDequeModClass.findNonOverloadedDecl(DefaultGetterName(nme.Constructor, 0))
     assert(clue(ArrayDequeModClass.getNonOverloadedDecl(DefaultGetterName(nme.Constructor, 1))).isEmpty)

test-sources/src/main/scala/simple_trees/DefaultParams.scala

@@ -2,4 +2,6 @@ package simple_trees
 
 class DefaultParams:
   def foo(x: Int, y: Int = 1, z: String = "hello"): String = s"$x $y $z"
+
+  def foo(x: Int, y: String): String = s"$x $y"
 end DefaultParams