Allow misindented continuation keywords

Also: align indentation in some code

Author: odersky

compiler/src/dotty/tools/backend/sjs/JSCodeGen.scala

@@ -2588,7 +2588,8 @@ class JSCodeGen()(implicit ctx: Context) {
       sym.info.paramNamess.flatten.zip(sym.info.paramInfoss.flatten)
 
     val wereRepeated = ctx.atPhase(ctx.elimRepeatedPhase) {
-      val list = for ((name, tpe) <- paramNamesAndTypes)
+      val list =
+        for ((name, tpe) <- paramNamesAndTypes)
         yield (name -> tpe.isRepeatedParam)
       list.toMap
     }

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -1234,6 +1234,9 @@ object Parsers {
       case _ => op
     }
 
+    def observeIndentedUnlessFollowedBy(followers: BitSet): Unit =
+      if !followers.contains(in.token) then in.observeIndented()
+
 /* ------------- TYPES ------------------------------------------------------ */
 
     /** Same as [[typ]], but if this results in a wildcard it emits a syntax error and
@@ -1637,7 +1640,7 @@ object Parsers {
           in.nextToken()
         }
         else
-          in.observeIndented()
+          observeIndentedUnlessFollowedBy(BitSet(THEN, DO))
           if (rewriteToNewSyntax(t.span))
             dropParensOrBraces(t.span.start, s"${tokenString(altToken)}")
         t
@@ -2298,7 +2301,7 @@ object Parsers {
                 dropParensOrBraces(start, if (in.token == YIELD || in.token == DO) "" else "do")
               }
             }
-            in.observeIndented()
+            observeIndentedUnlessFollowedBy(BitSet(YIELD, DO))
             res
           }
           else {

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

@@ -2174,7 +2174,8 @@ object messages {
       def symLocation(sym: Symbol) = {
         val lineDesc =
           if (sym.span.exists && sym.span != sym.owner.span)
-            s" at line ${sym.sourcePos.line + 1}" else ""
+            s" at line ${sym.sourcePos.line + 1}"
+          else ""
         i"in ${sym.owner}${lineDesc}"
       }
       val clashDescription =

compiler/src/dotty/tools/dotc/transform/Mixin.scala

@@ -254,7 +254,7 @@ class Mixin extends MiniPhase with SymTransformer { thisPhase =>
 
     def setters(mixin: ClassSymbol): List[Tree] =
       for (setter <- mixin.info.decls.filter(setr => setr.isSetter && !wasOneOf(setr, Deferred)))
-        yield transformFollowing(DefDef(mkForwarderSym(setter.asTerm), unitLiteral.withSpan(cls.span)))
+      yield transformFollowing(DefDef(mkForwarderSym(setter.asTerm), unitLiteral.withSpan(cls.span)))
 
     def mixinForwarders(mixin: ClassSymbol): List[Tree] =
       for (meth <- mixin.info.decls.toList if needsMixinForwarder(meth))