Drop support for Scala 2.11.x

.github/workflows/ci.yml

@@ -10,7 +10,7 @@ jobs:
       fail-fast: false
       matrix:
         java: [8, 11, 17]
-        scala: [2.11.x, 2.12.x, 2.13.x, 3.x]
+        scala: [2.12.x, 2.13.x, 3.x]
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3

README.md

@@ -13,7 +13,7 @@ This library's main strengths are:
 * Stability. It's been around and in wide use for more than a decade.
 * The codebase is modest in size and its internals are fairly simple.
 * It's plain vanilla Scala. No macros, code generation, or other magic is involved.
-* All versions of Scala (2.11, 2.12, 2.13, 3) are supported on all back ends (JVM, JS, Native).
+* Multiple versions of Scala (2.12, 2.13, 3) are supported on all back ends (JVM, JS, Native).
 
 Its main weaknesses are:
 

build.sbt

@@ -22,14 +22,11 @@ lazy val parserCombinators = crossProject(JVMPlatform, JSPlatform, NativePlatfor
     name := "scala-parser-combinators",
     scalaModuleAutomaticModuleName := Some("scala.util.parsing"),
 
-    crossScalaVersions := Seq("2.13.10", "2.12.17", "2.11.12", "3.2.1"),
+    crossScalaVersions := Seq("2.13.10", "2.12.17", "3.2.1"),
     scalaVersion := crossScalaVersions.value.head,
 
     libraryDependencies += "junit" % "junit" % "4.13.2" % Test,
     libraryDependencies += "com.github.sbt" % "junit-interface" % "0.13.3" % Test,
-    // so we can `@nowarn` in test code, but only in test code, so the dependency
-    // doesn't leak downstream. can be dropped when we drop 2.11 from the crossbuild
-    libraryDependencies += "org.scala-lang.modules" %% "scala-collection-compat" % "2.9.0" % Test,
 
     apiMappings ++= scalaInstance.value.libraryJars.collect {
       case file if file.getName.startsWith("scala-library") && file.getName.endsWith(".jar") =>

shared/src/main/scala-2.13-/scala/util/parsing/input/ScalaVersionSpecificPagedSeq.scala

@@ -13,5 +13,5 @@
 package scala.util.parsing.input
 
 private[input] trait ScalaVersionSpecificPagedSeq[T] {
-  // Nothing for 2.11 and 2.12!
+  // Nothing for 2.12!
 }