Fix regression test for #12128

To properly reproduce #12128, the regression test has some atypical
classpath requirements in addition to separate compilation.

Author: griggt

compiler/test/dotty/tools/dotc/CompilationTests.scala

@@ -325,6 +325,27 @@ class CompilationTests {
     compileFilesInDir("tests/init/neg", options).checkExpectedErrors()
     compileFilesInDir("tests/init/pos", options).checkCompile()
     compileFilesInDir("tests/init/crash", options.without("-Xfatal-warnings")).checkCompile()
+
+    // The regression test for i12128 has some atypical classpath requirements.
+    // The test consists of three files: (a) Reflect_1  (b) Macro_2  (c) Test_3
+    // which must be compiled separately. In addition:
+    //   - the output from (a) must be on the classpath while compiling (b)
+    //   - the output from (b) must be on the classpath while compiling (c)
+    //   - the output from (a) _must not_ be on the classpath while compiling (c)
+    locally {
+      val i12128Group = TestGroup("checkInit/i12128")
+      val i12128Options = options.without("-Xfatal-warnings")
+      val outDir1 = defaultOutputDir + i12128Group + "/Reflect_1/i12128/Reflect_1"
+      val outDir2 = defaultOutputDir + i12128Group + "/Macro_2/i12128/Macro_2"
+
+      val tests = List(
+        compileFile("tests/init/special/i12128/Reflect_1.scala", i12128Options)(i12128Group),
+        compileFile("tests/init/special/i12128/Macro_2.scala", i12128Options.withClasspath(outDir1))(i12128Group),
+        compileFile("tests/init/special/i12128/Test_3.scala", options.withClasspath(outDir2))(i12128Group)
+      ).map(_.keepOutput.checkCompile())
+
+      tests.foreach(_.delete())
+    }
   }
 }
 

tests/init/crash/i12128/Macro_2.scala renamed to tests/init/special/i12128/Macro_2.scala

@@ -1,6 +1,8 @@
 import scala.quoted._
 import scala.language.experimental.macros
 
+class Location(val line: Int)
+
 object MacroCompat {
   trait LocationMacro {
     inline implicit def generate: Location = ${ locationImpl() }

tests/init/crash/i12128/Reflect_1.scala renamed to tests/init/special/i12128/Reflect_1.scala

@@ -20,11 +20,11 @@ trait Context: // Dummy scala.reflect.macros.Context
     def New(tpe: Type, arg: Tree): Tree
   }
 
-  def enclosingPosition: Location
+  def enclosingPosition: Position
 
   trait Mirror {
     def staticClass(name: String): universe.Type
   }
   val mirror: Mirror
 
-class Location(val line: Int)
+class Position(val line: Int)