Fix unrelated typos in comments

Author: odersky

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

@@ -29,7 +29,7 @@ import StdNames._
  *   - eliminates some kinds of trees: Imports, NamedArgs
  *   - stubs out native methods
  *   - eliminates self tree in Template and self symbol in ClassInfo
- *   - collapsess all type trees to trees of class TypeTree
+ *   - collapses all type trees to trees of class TypeTree
  *   - converts idempotent expressions with constant types
  */
 class FirstTransform extends MiniPhaseTransform with InfoTransformer with AnnotationTransformer { thisTransformer =>
@@ -148,7 +148,7 @@ class FirstTransform extends MiniPhaseTransform with InfoTransformer with Annota
   override def transformTemplate(impl: Template)(implicit ctx: Context, info: TransformerInfo): Tree = {
     cpy.Template(impl)(self = EmptyValDef)
   }
-  
+
   override def transformDefDef(ddef: DefDef)(implicit ctx: Context, info: TransformerInfo) = {
     if (ddef.symbol.hasAnnotation(defn.NativeAnnot)) {
       ddef.symbol.resetFlag(Deferred)
@@ -168,13 +168,13 @@ class FirstTransform extends MiniPhaseTransform with InfoTransformer with Annota
   }
 
   override def transformIdent(tree: Ident)(implicit ctx: Context, info: TransformerInfo) =
-    if (tree.isType) TypeTree(tree.tpe).withPos(tree.pos) 
+    if (tree.isType) TypeTree(tree.tpe).withPos(tree.pos)
     else constToLiteral(tree)
 
   override def transformSelect(tree: Select)(implicit ctx: Context, info: TransformerInfo) =
-    if (tree.isType) TypeTree(tree.tpe).withPos(tree.pos) 
+    if (tree.isType) TypeTree(tree.tpe).withPos(tree.pos)
     else constToLiteral(tree)
-    
+
   override def transformTypeApply(tree: TypeApply)(implicit ctx: Context, info: TransformerInfo) =
     constToLiteral(tree)
 
@@ -183,7 +183,7 @@ class FirstTransform extends MiniPhaseTransform with InfoTransformer with Annota
 
   override def transformTyped(tree: Typed)(implicit ctx: Context, info: TransformerInfo) =
     constToLiteral(tree)
-    
+
   override def transformBlock(tree: Block)(implicit ctx: Context, info: TransformerInfo) =
     constToLiteral(tree)
 

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

@@ -234,7 +234,7 @@ object ProtoTypes {
     }
 
     /** The type of the argument `arg`.
-     *  @pre `arg` ahs been typed before
+     *  @pre `arg` has been typed before
      */
     def typeOfArg(arg: untpd.Tree)(implicit ctx: Context): Type =
       myTypedArg(arg).tpe