Error reporting improvements

src/dotty/tools/dotc/ast/Desugar.scala

@@ -9,7 +9,6 @@ import Decorators._
 import language.higherKinds
 import collection.mutable.ListBuffer
 import config.Printers._
-import typer.ErrorReporting.InfoString
 import typer.Mode
 
 object desugar {

src/dotty/tools/dotc/core/Contexts.scala

@@ -504,9 +504,6 @@ object Contexts {
 
     protected[dotc] val indentTab = "  "
 
-    /** Should warnings and errors containing non-sensical strings be suppressed? */
-    private[dotc] var suppressNonSensicalErrors = true
-
     def reset() = {
       for ((_, set) <- uniqueSets) set.clear()
       for (i <- 0 until classOfId.length) classOfId(i) = null

src/dotty/tools/dotc/core/Decorators.scala

@@ -3,7 +3,7 @@ package core
 
 import annotation.tailrec
 import Symbols._
-import Contexts._, Names._, Phases._, printing.Texts._, printing.Printer
+import Contexts._, Names._, Phases._, printing.Texts._, printing.Printer, printing.Showable
 import util.Positions.Position, util.SourcePosition
 import collection.mutable.ListBuffer
 import dotty.tools.dotc.transform.TreeTransforms._
@@ -136,5 +136,36 @@ object Decorators {
 
   implicit def sourcePos(pos: Position)(implicit ctx: Context): SourcePosition =
     ctx.source.atPos(pos)
+
+  /** The i"..." string interpolator adds two features to the s interpolator:
+   *  1) On all Showables, `show` is called instead of `toString`
+   *  2) Lists can be formatted using the desired separator between two `%` signs,
+   *     eg `i"myList = (${myList}%, %)"`
+   */
+  implicit class InfoString(val sc: StringContext) extends AnyVal {
+
+    def i(args: Any*)(implicit ctx: Context): String = {
+
+      def treatArg(arg: Any, suffix: String): (Any, String) = arg match {
+        case arg: Seq[_] if suffix.nonEmpty && suffix.head == '%' =>
+          val (rawsep, rest) = suffix.tail.span(_ != '%')
+          val sep = StringContext.treatEscapes(rawsep)
+          if (rest.nonEmpty) (arg map treatSingleArg mkString sep, rest.tail)
+          else (arg, suffix)
+        case _ =>
+          (treatSingleArg(arg), suffix)
+      }
+
+      def treatSingleArg(arg: Any) : Any = arg match {
+        case arg: Showable => arg.show
+        case _ => arg
+      }
+
+      val prefix :: suffixes = sc.parts.toList
+      val (args1, suffixes1) = (args, suffixes).zipped.map(treatArg(_, _)).unzip
+      new StringContext(prefix :: suffixes1.toList: _*).s(args1: _*)
+    }
+  }
+
 }
 

src/dotty/tools/dotc/reporting/Reporter.scala

@@ -10,26 +10,27 @@ import collection.mutable
 import config.Settings.Setting
 import config.Printers
 import java.lang.System.currentTimeMillis
+import typer.ErrorReporting.DiagnosticString
 
 object Reporter {
 
-  class Diagnostic(msgFn: => String, val pos: SourcePosition, val severity: Severity, base: ContextBase) extends Exception {
+  class Diagnostic(msgFn: => String, val pos: SourcePosition, val severity: Severity) extends Exception {
+    import DiagnosticString._
     private var myMsg: String = null
-    private var myIsSuppressed: Boolean = false
+    private var myIsNonSensical: Boolean = false
     def msg: String = {
-      if (myMsg == null)
-        try myMsg = msgFn
-        catch {
-          case ex: SuppressedMessage =>
-            myIsSuppressed = true
-            val saved = base.suppressNonSensicalErrors
-            base.suppressNonSensicalErrors = false
-            try myMsg = msgFn
-            finally base.suppressNonSensicalErrors = saved
+      if (myMsg == null) {
+        myMsg = msgFn
+        if (myMsg.contains(nonSensicalStartTag)) {
+          myIsNonSensical = true
+          // myMsg might be composed of several d"..." invocations -> nested nonsensical tags possible
+          myMsg = myMsg.replaceAllLiterally(nonSensicalStartTag, "").replaceAllLiterally(nonSensicalEndTag, "")
         }
+      }
       myMsg
     }
-    def isSuppressed = { msg; myIsSuppressed }
+    def isNonSensical = { msg; myIsNonSensical }
+    def isSuppressed(implicit ctx: Context): Boolean = !ctx.settings.YshowSuppressedErrors.value && isNonSensical
     override def toString = s"$severity at $pos: $msg"
     override def getMessage() = msg
 
@@ -38,8 +39,8 @@ object Reporter {
       else severity
   }
 
-  def Diagnostic(msgFn: => String, pos: SourcePosition, severity: Severity)(implicit ctx: Context) =
-    new Diagnostic(msgFn, pos, severity, ctx.base)
+  def Diagnostic(msgFn: => String, pos: SourcePosition, severity: Severity) =
+    new Diagnostic(msgFn, pos, severity)
 
   class Severity(val level: Int) extends AnyVal {
     override def toString = this match {
@@ -71,8 +72,6 @@ object Reporter {
     case UncheckedWARNING   => ctx.settings.unchecked
     case FeatureWARNING     => ctx.settings.feature
   }
-
-  class SuppressedMessage extends Exception
 }
 
 import Reporter._
@@ -221,7 +220,7 @@ abstract class Reporter {
   def report(d: Diagnostic)(implicit ctx: Context): Unit =
     if (!isHidden(d)) {
       doReport(d)
-      count(d.promotedSeverity.level) += 1
+      if (!d.isSuppressed) count(d.promotedSeverity.level) += 1
     }
 
   def incomplete(d: Diagnostic)(implicit ctx: Context): Unit =

src/dotty/tools/dotc/transform/TreeChecker.scala

@@ -10,6 +10,7 @@ import core.Symbols._
 import core.Types._
 import core.Constants._
 import core.StdNames._
+import core.Decorators._
 import core.transform.Erasure.isUnboundedGeneric
 import typer.ErrorReporting._
 import ast.Trees._

src/dotty/tools/dotc/typer/Applications.scala

@@ -588,9 +588,9 @@ trait Applications extends Compatibility { self: Typer =>
       def extractorMemberType(tp: Type, name: Name) = {
         val ref = tp member name
         if (ref.isOverloaded)
-          errorType(s"Overloaded reference to ${ref.show} is not allowed in extractor", tree.pos)
+          errorType(i"Overloaded reference to $ref is not allowed in extractor", tree.pos)
         else if (ref.info.isInstanceOf[PolyType])
-          errorType(s"Reference to polymorphic ${ref.show}: ${ref.info.show} is not allowed in extractor", tree.pos)
+          errorType(i"Reference to polymorphic $ref: ${ref.info} is not allowed in extractor", tree.pos)
         else
           ref.info.widenExpr.dealias
       }
@@ -618,7 +618,7 @@ trait Applications extends Compatibility { self: Typer =>
       if (unapplyResult derivesFrom defn.SeqClass) seqSelector :: Nil
       else if (unapplyResult isRef defn.BooleanClass) Nil
       else {
-        ctx.error(s"${unapplyResult.show} is not a valid result type of an unapply method of an extractor", tree.pos)
+        ctx.error(i"$unapplyResult is not a valid result type of an unapply method of an extractor", tree.pos)
         Nil
       }
     }
@@ -636,7 +636,7 @@ trait Applications extends Compatibility { self: Typer =>
     unapplyFn.tpe.widen match {
       case mt: MethodType if mt.paramTypes.length == 1 && !mt.isDependent =>
         val unapplyArgType = mt.paramTypes.head
-        unapp.println(s"unapp arg tpe = ${unapplyArgType.show}, pt = ${pt.show}")
+        unapp.println(i"unapp arg tpe = $unapplyArgType, pt = $pt")
         def wpt = widenForMatchSelector(pt) // needed?
         val ownType =
           if (pt <:< unapplyArgType) {
@@ -647,7 +647,7 @@ trait Applications extends Compatibility { self: Typer =>
             maximizeType(unapplyArgType) match {
               case Some(tvar) =>
                 def msg =
-                  i"""There is no best instantiation of pattern type $unapplyArgType
+                  d"""There is no best instantiation of pattern type $unapplyArgType
                      |that makes it a subtype of selector type $pt.
                      |Non-variant type variable ${tvar.origin} cannot be uniquely instantiated.""".stripMargin
                 if (fromScala2x) {
@@ -671,7 +671,7 @@ trait Applications extends Compatibility { self: Typer =>
             unapp.println("Neither sub nor super")
             unapp.println(TypeComparer.explained(implicit ctx => unapplyArgType <:< wpt))
             errorType(
-              i"Pattern type $unapplyArgType is neither a subtype nor a supertype of selector type $wpt",
+              d"Pattern type $unapplyArgType is neither a subtype nor a supertype of selector type $wpt",
               tree.pos)
           }
 
@@ -692,7 +692,7 @@ trait Applications extends Compatibility { self: Typer =>
           case _ => args
         }
         if (argTypes.length != bunchedArgs.length) {
-          ctx.error(i"wrong number of argument patterns for $qual; expected: ($argTypes%, %)", tree.pos)
+          ctx.error(d"wrong number of argument patterns for $qual; expected: ($argTypes%, %)", tree.pos)
           argTypes = argTypes.take(args.length) ++
             List.fill(argTypes.length - args.length)(WildcardType)
         }

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

@@ -14,7 +14,7 @@ import util.{Stats, SimpleMap}
 import util.common._
 import Decorators._
 import Uniques._
-import ErrorReporting.{errorType, InfoString}
+import ErrorReporting.{errorType, DiagnosticString}
 import config.Printers._
 import collection.mutable
 
@@ -27,7 +27,7 @@ trait Checking {
   def checkValue(tree: Tree, proto: Type)(implicit ctx: Context): tree.type = {
     if (!proto.isInstanceOf[SelectionProto]) {
       val sym = tree.tpe.termSymbol
-      if ((sym is Package) || (sym is JavaModule)) ctx.error(i"$sym is not a value", tree.pos)
+      if ((sym is Package) || (sym is JavaModule)) ctx.error(d"$sym is not a value", tree.pos)
     }
     tree
   }
@@ -38,21 +38,21 @@ trait Checking {
     def substituted(tp: Type) = tp.substParams(poly, argTypes)
     for ((arg, bounds) <- args zip poly.paramBounds) {
       def notConforms(which: String, bound: Type) =
-        ctx.error(i"Type argument ${arg.tpe} does not conform to $which bound $bound", arg.pos)
+        ctx.error(d"Type argument ${arg.tpe} does not conform to $which bound $bound", arg.pos)
       if (!(arg.tpe <:< substituted(bounds.hi))) notConforms("upper", bounds.hi)
       if (!(bounds.lo <:< arg.tpe)) notConforms("lower", bounds.lo)
     }
   }
 
   /** Check that type `tp` is stable. */
   def checkStable(tp: Type, pos: Position)(implicit ctx: Context): Unit =
-    if (!tp.isStable) ctx.error(i"$tp is not stable", pos)
+    if (!tp.isStable) ctx.error(d"$tp is not stable", pos)
 
   /** Check that type `tp` is a legal prefix for '#'.
    *  @return The type itself
    */
   def checkLegalPrefix(tp: Type, pos: Position)(implicit ctx: Context): Unit =
-    if (!tp.isLegalPrefix) ctx.error(i"$tp is not a valid prefix for '#'", pos)
+    if (!tp.isLegalPrefix) ctx.error(d"$tp is not a valid prefix for '#'", pos)
 
  /** Check that `tp` is a class type with a stable prefix. Also, if `isFirst` is
    *  false check that `tp` is a trait.
@@ -62,10 +62,10 @@ trait Checking {
     tp.underlyingClassRef match {
       case tref: TypeRef =>
         checkStable(tref.prefix, pos)
-        if (traitReq && !(tref.symbol is Trait)) ctx.error(i"$tref is not a trait", pos)
+        if (traitReq && !(tref.symbol is Trait)) ctx.error(d"$tref is not a trait", pos)
         tp
     case _ =>
-      ctx.error(i"$tp is not a class type", pos)
+      ctx.error(d"$tp is not a class type", pos)
       defn.ObjectClass.typeRef
   }
 
@@ -74,7 +74,7 @@ trait Checking {
     case tpt: untpd.DerivedTypeTree =>
     case TypeTree(untpd.EmptyTree) =>
       val resStr = if (defTree.isInstanceOf[untpd.DefDef]) "result " else ""
-      ctx.error(i"${resStr}type of implicit definition needs to be given explicitly", defTree.pos)
+      ctx.error(d"${resStr}type of implicit definition needs to be given explicitly", defTree.pos)
     case _ =>
   }
 
@@ -96,7 +96,7 @@ trait Checking {
     case tp: RefinedType =>
       tp.derivedRefinedType(tp.parent, tp.refinedName, checkFeasible(tp.refinedInfo, pos, where))
     case tp @ TypeBounds(lo, hi) if !(lo <:< hi) =>
-      ctx.error(i"no type exists between low bound $lo and high bound $hi$where", pos)
+      ctx.error(d"no type exists between low bound $lo and high bound $hi$where", pos)
       tp.derivedTypeAlias(hi)
     case _ =>
       tp
@@ -113,17 +113,17 @@ trait Checking {
         typr.println(i"conflict? $decl $other")
         if (decl.signature matches other.signature) {
           def doubleDefError(decl: Symbol, other: Symbol): Unit = {
-            def ofType = if (decl.isType) "" else i": ${other.info}"
+            def ofType = if (decl.isType) "" else d": ${other.info}"
             def explanation =
               if (!decl.isSourceMethod) ""
               else "\n (both definitions have the same erased type signature)"
-            ctx.error(i"$decl is already defined as $other$ofType$explanation", decl.pos)
+            ctx.error(d"$decl is already defined as $other$ofType$explanation", decl.pos)
           }
           if (decl is Synthetic) doubleDefError(other, decl)
           else doubleDefError(decl, other)
         }
         if ((decl is HasDefaultParams) && (other is HasDefaultParams)) {
-          ctx.error(i"two or more overloaded variants of $decl have default arguments")
+          ctx.error(d"two or more overloaded variants of $decl have default arguments")
           decl resetFlag HasDefaultParams
         }
       }