Merge pull request #6797 from dotty-staging/fix-#6795

Fix #6795: Print flagString

Author: anatoliykmetyuk

compiler/src/dotty/tools/dotc/core/unpickleScala2/Scala2Unpickler.scala

@@ -464,9 +464,9 @@ class Scala2Unpickler(bytes: Array[Byte], classRoot: ClassDenotation, moduleClas
     def isModuleClassRoot = nameMatches(moduleClassRoot.name) && (owner == moduleClassRoot.owner) && flags.is(Module)
     def isModuleRoot = nameMatches(moduleClassRoot.name.sourceModuleName) && (owner == moduleClassRoot.owner) && flags.is(Module)
 
-    //if (isClassRoot) println(s"classRoot of $classRoot found at $readIndex, flags = $flags") // !!! DEBUG
-    //if (isModuleRoot) println(s"moduleRoot of $moduleRoot found at $readIndex, flags = $flags") // !!! DEBUG
-    //if (isModuleClassRoot) println(s"moduleClassRoot of $moduleClassRoot found at $readIndex, flags = $flags") // !!! DEBUG
+    //if (isClassRoot) println(s"classRoot of $classRoot found at $readIndex, flags = ${flags.flagsString}") // !!! DEBUG
+    //if (isModuleRoot) println(s"moduleRoot of $moduleRoot found at $readIndex, flags = ${flags.flagsString}") // !!! DEBUG
+    //if (isModuleClassRoot) println(s"moduleClassRoot of $moduleClassRoot found at $readIndex, flags = ${flags.flagsString}") // !!! DEBUG
 
     def completeRoot(denot: ClassDenotation, completer: LazyType): Symbol = {
       denot.setFlag(flags)

compiler/src/dotty/tools/dotc/reporting/diagnostic/messages.scala

@@ -1504,7 +1504,7 @@ object messages {
   case class AbstractMemberMayNotHaveModifier(sym: Symbol, flag: FlagSet)(
     implicit ctx: Context)
     extends Message(AbstractMemberMayNotHaveModifierID) {
-    val msg: String = em"""${hl("abstract")} $sym may not have `$flag' modifier"""
+    val msg: String = em"""${hl("abstract")} $sym may not have `${flag.flagsString}` modifier"""
     val kind: String = "Syntax"
     val explanation: String = ""
   }
@@ -1697,7 +1697,7 @@ object messages {
   case class ModifiersNotAllowed(flags: FlagSet, printableType: Option[String])(implicit ctx: Context)
     extends Message(ModifiersNotAllowedID) {
     val kind: String = "Syntax"
-    val msg: String = em"Modifier(s) $flags not allowed for ${printableType.getOrElse("combination")}"
+    val msg: String = em"Modifier(s) `${flags.flagsString}` not allowed for ${printableType.getOrElse("combination")}"
     val explanation: String = {
       val first = "sealed def y: Int = 1"
       val second = "sealed lazy class z"

compiler/src/dotty/tools/dotc/typer/Checking.scala

@@ -394,10 +394,10 @@ object Checking {
     def checkNoConflict(flag1: FlagSet, flag2: FlagSet, msg: => String) =
       if (sym.isAllOf(flag1 | flag2)) fail(msg)
     def checkCombination(flag1: FlagSet, flag2: FlagSet) =
-      checkNoConflict(flag1, flag2, i"illegal combination of modifiers: `$flag1` and `$flag2` for: $sym")
+      checkNoConflict(flag1, flag2, i"illegal combination of modifiers: `${flag1.flagsString}` and `${flag2.flagsString}` for: $sym")
     def checkApplicable(flag: FlagSet, ok: Boolean) =
       if (!ok && !sym.is(Synthetic))
-        fail(i"modifier `$flag` is not allowed for this definition")
+        fail(i"modifier `${flag.flagsString}` is not allowed for this definition")
 
     if (sym.is(Inline) &&
           (  sym.is(ParamAccessor) && sym.owner.isClass

compiler/src/dotty/tools/dotc/typer/Namer.scala

@@ -284,7 +284,7 @@ class Namer { typer: Typer =>
           case _ => (flags.isTermFlags, flags.toTermFlags, "value")
         }
         if (!ok)
-          ctx.error(i"modifier(s) `$flags' incompatible with $kind definition", tree.sourcePos)
+          ctx.error(i"modifier(s) `${flags.flagsString}` incompatible with $kind definition", tree.sourcePos)
         adapted
       }
 

tests/neg/i6795-b.check

@@ -0,0 +1,6 @@
+-- [E083] Syntax Error: tests/neg/i6795-b.scala:1:11 -------------------------------------------------------------------
+1 |sealed def y: Int = 1 // error
+  |           ^
+  |           Modifier(s) `sealed` not allowed for method
+
+longer explanation available when compiling with `-explain`

tests/neg/i6795-b.scala

@@ -0,0 +1 @@
+sealed def y: Int = 1 // error

tests/neg/i6795.check

@@ -0,0 +1,4 @@
+-- Error: tests/neg/i6795.scala:1:13 -----------------------------------------------------------------------------------
+1 |erased class Foo // error
+  |^^^^^^^^^^^^^^^^
+  |modifier(s) `erased` incompatible with type definition

tests/neg/i6795.scala

@@ -0,0 +1 @@
+erased class Foo // error