From 79f32d4365343cddea352b06849e5a4c2e1dd3e0 Mon Sep 17 00:00:00 2001
From: Nicolas Stucki <nicolas.stucki@gmail.com>
Date: Wed, 8 May 2019 18:51:57 +0200
Subject: [PATCH] Add regression test

Show how it is possible to test error reporting within a macro without an additional framework
---
 .../Macros_1.scala                            | 71 +++++++++++++++++++
 .../Test_2.scala                              | 24 +++++++
 2 files changed, 95 insertions(+)
 create mode 100644 tests/run-macros/tasty-string-interpolation-reporter-test/Macros_1.scala
 create mode 100644 tests/run-macros/tasty-string-interpolation-reporter-test/Test_2.scala

diff --git a/tests/run-macros/tasty-string-interpolation-reporter-test/Macros_1.scala b/tests/run-macros/tasty-string-interpolation-reporter-test/Macros_1.scala
new file mode 100644
index 000000000000..622947491904
--- /dev/null
+++ b/tests/run-macros/tasty-string-interpolation-reporter-test/Macros_1.scala
@@ -0,0 +1,71 @@
+import scala.quoted._
+import scala.quoted.autolift._
+import scala.quoted.matching._
+import scala.tasty.Reflection
+
+import scala.language.implicitConversions
+
+object Foo {
+  implicit object StringContextOps {
+    inline def (ctx: => StringContext) foo (args: => Any*): String = ${ Macro.foo('ctx, 'args) }
+  }
+}
+
+
+object TestFooErrors { // Defined in tests
+  implicit object StringContextOps {
+    inline def (ctx: => StringContext) foo (args: => Any*): List[(Int, Int, Int, String)] = ${ Macro.fooErrors('ctx, 'args) }
+  }
+}
+
+object Macro {
+
+  def foo(sc: Expr[StringContext], argsExpr: Expr[Seq[Any]]) given (reflect: Reflection): Expr[String] = {
+    (sc, argsExpr) match {
+      case ('{ StringContext(${ExprSeq(parts)}: _*) }, ExprSeq(args)) =>
+        val reporter = new Reporter {
+          def errorOnPart(msg: String, partIdx: Int): Unit = {
+            import reflect._
+            error(msg, parts(partIdx).unseal.pos)
+          }
+        }
+        fooCore(parts, args, reporter)
+    }
+  }
+
+  def fooErrors(sc: Expr[StringContext], argsExpr: Expr[Seq[Any]]) given (reflect: Reflection): Expr[List[(Int, Int, Int, String)]] = {
+    (sc, argsExpr) match {
+      case ('{ StringContext(${ExprSeq(parts)}: _*) }, ExprSeq(args)) =>
+        val errors = List.newBuilder[Expr[(Int, Int, Int, String)]]
+        val reporter = new Reporter {
+          def errorOnPart(msg: String, partIdx: Int): Unit = {
+            import reflect._
+            val pos = parts(partIdx).unseal.pos
+            errors += '{ Tuple4($partIdx, ${pos.start}, ${pos.end}, $msg) }
+          }
+        }
+        fooCore(parts, args, reporter) // Discard result
+        errors.result().toExprOfList
+    }
+
+
+  }
+
+
+  private def fooCore(parts: Seq[Expr[String]], args: Seq[Expr[Any]], reporter: Reporter) given Reflection: Expr[String] = {
+    for ((part, idx) <- parts.zipWithIndex) {
+      val Const(v: String) = part
+      if (v.contains("#"))
+        reporter.errorOnPart("Cannot use #", idx)
+    }
+
+    '{ StringContext(${parts.toList.toExprOfList}: _*).s(${args.toList.toExprOfList}: _*) }
+  }
+
+
+  trait Reporter {
+    def errorOnPart(msg: String, partIdx: Int): Unit
+  }
+
+
+}
diff --git a/tests/run-macros/tasty-string-interpolation-reporter-test/Test_2.scala b/tests/run-macros/tasty-string-interpolation-reporter-test/Test_2.scala
new file mode 100644
index 000000000000..8b9424bfecb0
--- /dev/null
+++ b/tests/run-macros/tasty-string-interpolation-reporter-test/Test_2.scala
@@ -0,0 +1,24 @@
+
+object Test {
+
+  def main(args: Array[String]): Unit = {
+    posTests()
+    negTests()
+  }
+
+  def posTests() = {
+    import Foo._
+    assertEquals(foo"abc${"123"}def", "abc123def")
+  }
+
+  def negTests() = {
+    import TestFooErrors._
+    assertEquals(foo"a#c${"123"}def", List((0, 256, 259, "Cannot use #")))
+    assertEquals(foo"abc${"123"}#ef", List((1, 342, 345, "Cannot use #")))
+    assertEquals(foo"a#c${"123"}#ef", List((0, 406, 409, "Cannot use #"), (1, 417, 420, "Cannot use #")))
+  }
+
+  def assertEquals(actual: Any, expected: Any): Unit = {
+    assert(actual == expected, s"actual: $actual\nbut expected: $expected")
+  }
+}