Add regression test and imporve -Xprint-suspension message (#19688)

Closes #19526

compiler/src/dotty/tools/dotc/Run.scala

@@ -141,7 +141,7 @@ class Run(comp: Compiler, ictx: Context) extends ImplicitRunInfo with Constraint
                 |"""
       val enableXprintSuspensionHint =
         if ctx.settings.XprintSuspension.value then ""
-        else "\n\nCompiling with  -Xprint-suspension   gives more information."
+        else "\n\nCompile with -Xprint-suspension for information."
       report.error(em"""Cyclic macro dependencies $where
                     |Compilation stopped since no further progress can be made.
                     |

tests/neg-macros/annot-suspend-cycle.check

@@ -9,4 +9,4 @@ Compilation stopped since no further progress can be made.
 
 To fix this, place macros in one set of files and their callers in another.
 
-Compiling with  -Xprint-suspension   gives more information.
+Compile with -Xprint-suspension for information.

tests/neg-macros/i19526.check

@@ -0,0 +1,6 @@
+Cyclic macro dependencies in tests/neg-macros/i19526/Test.scala.
+Compilation stopped since no further progress can be made.
+
+To fix this, place macros in one set of files and their callers in another.
+
+Compile with -Xprint-suspension for information.

tests/neg-macros/i19526/Macro.scala

@@ -0,0 +1,15 @@
+package crash.test
+
+import scala.language.dynamics
+
+import scala.quoted.*
+
+object Export extends Dynamic:
+  inline def applyDynamic(name: "apply")(inline args: Any*): Stack = ${
+    applyDynamicImpl('args)
+  }
+
+  def applyDynamicImpl(args: Expr[Seq[Any]])(using Quotes): Expr[Stack] =
+    import quotes.reflect.*
+
+    '{ Stack("", Vector.empty) }

tests/neg-macros/i19526/Test.scala

@@ -0,0 +1,14 @@
+package crash.test
+
+case class Stack private[crash] (
+    exports: String,
+    dependsOn: Vector[Int]
+)
+
+trait StackFactory:
+  val exports: Export.type = Export
+
+  def apply(dependsOn: Int*): Stack =
+    Export().copy(dependsOn = dependsOn.toVector)
+
+// nopos-error

tests/neg-macros/macros-in-same-project-4.check

@@ -3,4 +3,4 @@ Compilation stopped since no further progress can be made.
 
 To fix this, place macros in one set of files and their callers in another.
 
-Compiling with  -Xprint-suspension   gives more information.
+Compile with -Xprint-suspension for information.

tests/pos-macros/i19526b/Macro.scala

@@ -0,0 +1,15 @@
+package crash.test
+
+import scala.language.dynamics
+
+import scala.quoted.*
+
+object Export extends Dynamic:
+  inline def applyDynamic(name: "apply")(inline args: Any*): Stack = ${
+    applyDynamicImpl('args)
+  }
+
+  def applyDynamicImpl(args: Expr[Seq[Any]])(using Quotes): Expr[Stack] =
+    import quotes.reflect.*
+
+    '{ Stack("", Vector.empty) }

tests/pos-macros/i19526b/Test.scala

@@ -0,0 +1,16 @@
+package crash.test
+
+case class Stack private[crash] (
+    exports: String,
+    dependsOn: Vector[Int]
+)
+
+object Stack:
+  @annotation.publicInBinary
+  private[crash] def apply(exports: String, dependsOn: Vector[Int]): Stack = new Stack(exports, dependsOn)
+
+trait StackFactory:
+  val exports: Export.type = Export
+
+  def apply(dependsOn: Int*): Stack =
+    Export().copy(dependsOn = dependsOn.toVector)