Allow -_ and +_ as type names in order to support lastest changes

for kind-projector that works under -Xsource3 flag.
scalameta · May 18, 2021 · 1c3bbdf · 1c3bbdf
1 parent d6a864b
commit 1c3bbdf
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Showing 4 changed files with 38 additions and 7 deletions.
diff --git a/scalameta/dialects/shared/src/main/scala/scala/meta/Dialect.scala b/scalameta/dialects/shared/src/main/scala/scala/meta/Dialect.scala
@@ -158,7 +158,12 @@ final class Dialect private (
     // Scala 3 no longer allows def hello(){} - `=` is always needed
     val allowProcedureSyntax: Boolean,
     // Scala 3 no longer allows `do {...} while(...)`
-    val allowDoWhile: Boolean
+    val allowDoWhile: Boolean,
+    /* Kind-project support
+     * works under -Xsource3 flag
+     * https://github.com/scala/scala/pull/9605
+     */
+    val allowPlusMinusUnderscoreIdent: Boolean
 ) extends Product with Serializable {
 
   // NOTE(olafur) checklist for adding a new dialect field in a binary compatible way:
@@ -253,7 +258,8 @@ final class Dialect private (
       allowAsForImportRename = false,
       allowStarWildcardImport = false,
       allowProcedureSyntax = true,
-      allowDoWhile = true
+      allowDoWhile = true,
+      allowPlusMinusUnderscoreIdent = false
       // NOTE(olafur): declare the default value for new fields above this comment.
     )
   }
@@ -455,6 +461,10 @@ final class Dialect private (
   def withAllowDoWhile(newValue: Boolean): Dialect = {
     privateCopy(allowDoWhile = newValue)
   }
+
+  def withAllowPlusMinusUnderscoreIdent(newValue: Boolean): Dialect = {
+    privateCopy(allowPlusMinusUnderscoreIdent = newValue)
+  }
   // NOTE(olafur): add the next `withX()` method above this comment. Please try
   // to use consistent formatting, use `newValue` as the parameter name and wrap
   // the body inside curly braces.
@@ -520,7 +530,8 @@ final class Dialect private (
       allowAsRenames: Boolean = this.allowAsForImportRename,
       allowStarWildcardImport: Boolean = this.allowStarWildcardImport,
       allowProcedureSyntax: Boolean = this.allowProcedureSyntax,
-      allowDoWhile: Boolean = this.allowDoWhile
+      allowDoWhile: Boolean = this.allowDoWhile,
+      allowPlusMinusUnderscoreIdent: Boolean = this.allowPlusMinusUnderscoreIdent
       // NOTE(olafur): add the next parameter above this comment.
   ): Dialect = {
     new Dialect(
@@ -583,7 +594,8 @@ final class Dialect private (
       allowAsRenames,
       allowStarWildcardImport,
       allowProcedureSyntax,
-      allowDoWhile
+      allowDoWhile,
+      allowPlusMinusUnderscoreIdent
       // NOTE(olafur): add the next argument above this comment.
     )
   }

diff --git a/scalameta/dialects/shared/src/main/scala/scala/meta/dialects/package.scala b/scalameta/dialects/shared/src/main/scala/scala/meta/dialects/package.scala
@@ -69,6 +69,7 @@ package object dialects {
     .withAllowInfixMods(true)
     .withAllowPostfixStarVarargSplices(true)
     .withAllowAndTypes(true)
+    .withAllowPlusMinusUnderscoreIdent(true)
 
   /**
    *  Dialect starting with  Scala 2.12.14 for `-Xsource:3` option
@@ -81,6 +82,7 @@ package object dialects {
     .withAllowInfixMods(true)
     .withAllowPostfixStarVarargSplices(true)
     .withAllowAndTypes(true)
+    .withAllowPlusMinusUnderscoreIdent(true)
 
   implicit val Scala = Scala213 // alias for latest Scala dialect.
 
@@ -152,6 +154,7 @@ package object dialects {
     .withAllowStarWildcardImport(true)
     .withAllowProcedureSyntax(false)
     .withAllowDoWhile(false)
+    .withAllowPlusMinusUnderscoreIdent(true)
 
   @deprecated("Use Scala3 instead", "4.4.2")
   implicit val Dotty = Scala3

diff --git a/scalameta/parsers/shared/src/main/scala/scala/meta/internal/parsers/ScalametaParser.scala b/scalameta/parsers/shared/src/main/scala/scala/meta/internal/parsers/ScalametaParser.scala
@@ -1729,12 +1729,21 @@ class ScalametaParser(input: Input)(implicit dialect: Dialect) { parser =>
           Type.Macro(macroSplice())
         case Ident("?") if dialect.allowQuestionMarkPlaceholder =>
           next(); atPos(in.prevTokenPos, auto)(Type.Placeholder(typeBounds()))
-        case Literal() =>
-          if (dialect.allowLiteralTypes) literal()
-          else syntaxError(s"$dialect doesn't support literal types", at = path())
+        case ident: Ident
+            if (ident.value == "+" || ident.value == "-") &&
+              ahead(token.is[Underscore]) &&
+              dialect.allowPlusMinusUnderscoreIdent =>
+          autoPos {
+            accept[Ident]
+            accept[Underscore]
+            Type.Name(s"${ident.value}_")
+          }
         case Ident("-") if ahead { token.is[NumericLiteral] } && dialect.allowLiteralTypes =>
           val term = termName()
           atPos(term, auto)(literal(isNegated = true))
+        case Literal() =>
+          if (dialect.allowLiteralTypes) literal()
+          else syntaxError(s"$dialect doesn't support literal types", at = path())
         case _ =>
           val ref = path() match {
             case q: Quasi => q.become[Term.Ref.Quasi]

diff --git a/tests/shared/src/test/scala/scala/meta/tests/parsers/TypeSuite.scala b/tests/shared/src/test/scala/scala/meta/tests/parsers/TypeSuite.scala
@@ -159,4 +159,11 @@ class TypeSuite extends ParseSuite {
     assertNoDiff(exceptionScala2.shortMessage, "illegal literal type (), use Unit instead")
 
   }
+
+  test("plus-minus-then-undescore-source3") {
+    val Type.Function(List(Type.Name("+_")), Type.Name("Int")) =
+      tpe("+_ => Int")(dialects.Scala213Source3)
+    val Type.Apply(Type.Name("Option"), List(Type.Name("-_"))) =
+      tpe("Option[- _]")(dialects.Scala213Source3)
+  }
 }