Rename "frontend" phase to "typer"

That makes it the same as for scalac. Aligning terminology helps switching between
the two codebases. Also, "frontend" is a bit off, since it is technically two phases,
not one.

Author: odersky

compiler/src/dotty/tools/dotc/config/CompilerCommand.scala

@@ -23,7 +23,7 @@ object CompilerCommand {
     |  - (partial) phase names with an optional "+" suffix to include the next phase
     |  - the string "all"
     |  example: -Xprint:all prints all phases.
-    |  example: -Xprint:front,mixin prints the frontend and mixin phases.
+    |  example: -Xprint:typer,mixin prints the typer and mixin phases.
     |  example: -Ylog:erasure+ logs the erasure phase and the phase after the erasure phase.
     |           This is useful because during the tree transform of phase X, we often
     |           already are in phase X + 1.

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

@@ -136,5 +136,5 @@ class FrontEnd extends Phase {
 }
 
 object FrontEnd {
-  val name: String = "frontend"
+  val name: String = "typer"
 }

compiler/test/dotc/comptest.scala

@@ -25,6 +25,6 @@ object comptest extends ParallelTesting {
         dotcDir + "tools/dotc/core/Types.scala",
         dotcDir + "tools/dotc/ast/Trees.scala"
       ),
-      TestFlags("", Array("-Ylog:frontend", "-Xprompt"))
+      TestFlags("", Array("-Ylog:typer", "-Xprompt"))
   )(TestGroup("comptest"))
 }

compiler/test/dotty/tools/dotc/printing/PrintingTest.scala

@@ -19,7 +19,7 @@ import org.junit.Test
 
 class PrintingTest {
   val testsDir = "tests/printing"
-  val options = List("-Xprint:frontend", "-color:never", "-classpath", TestConfiguration.basicClasspath)
+  val options = List("-Xprint:typer", "-color:never", "-classpath", TestConfiguration.basicClasspath)
 
   private def fileContent(filePath: String): List[String] =
     if (new File(filePath).exists)

docs/docs/contributing/debugging.md

@@ -91,16 +91,16 @@ assertPositioned(tree.reporting(s"Tree is: $result"))
 `def (a: A) reporting(f: given WrappedResult[T] => String, p: Printer = Printers.default): A` is defined on all types. The function `f` can be written without the argument since the argument is `given`. The `result` variable is a part of the `WrapperResult` – a tiny framework powering the `reporting` function. Basically, whenever you are using `reporting` on an object `A`, you can use the `result: A` variable from this function and it will be equal to the object you are calling `reporting` on.
 
 ## Printing out trees after phases
-To print out the trees you are compiling after Frontend (scanner, parser, namer, typer) phase:
+To print out the trees you are compiling after the FrontEnd (scanner, parser, namer, typer) phases:
 
 ```shell
-dotc -Xprint:frontend ../issues/Playground.scala
+dotc -Xprint:typer ../issues/Playground.scala
 ```
 
 To print out the trees after Frontend and CollectSuperCalls phases:
 
 ```shell
-dotc -Xprint:frontend,collectSuperCalls ../issues/Playground.scala
+dotc -Xprint:typer,collectSuperCalls ../issues/Playground.scala
 ```
 
 To print out the trees after all phases:
@@ -176,7 +176,7 @@ And is to be used as:
 dotc -Yprint-pos  ../issues/Playground.scala
 ```
 
-If used, all the trees output with `show` or via `-Xprint:frontend` will also have positions attached to them, e.g.:
+If used, all the trees output with `show` or via `-Xprint:typer` will also have positions attached to them, e.g.:
 
 ```scala
 package <empty>@<Playground.scala:1> {
@@ -204,7 +204,7 @@ package <empty>@<Playground.scala:1> {
 Every [Positioned](https://github.com/lampepfl/dotty/blob/10526a7d0aa8910729b6036ee51942e05b71abf6/compiler/src/dotty/tools/dotc/ast/Positioned.scala) (a parent class of `Tree`) object has a `uniqueId` field. It is an integer that is unique for that tree and doesn't change from compile run to compile run. You can output these IDs from any printer (such as the ones used by `.show` and `-Xprint`) via `-Yshow-tree-ids` flag, e.g.:
 
 ```shell
-dotc -Xprint:frontend -Yshow-tree-ids  ../issues/Playground.scala
+dotc -Xprint:typer -Yshow-tree-ids  ../issues/Playground.scala
 ```
 
 Gives:
@@ -363,4 +363,4 @@ trace.force(i"typing $tree", typr, show = true) { // ...
 ```
 
 ### Reporter
-Defined in [Reporter.scala](https://github.com/lampepfl/dotty/blob/10526a7d0aa8910729b6036ee51942e05b71abf6/compiler/src/dotty/tools/dotc/reporting/Reporter.scala). Enables calls such as `ctx.log`, `ctx.error` etc. To enable, run dotc with `-Ylog:frontend` option.
+Defined in [Reporter.scala](https://github.com/lampepfl/dotty/blob/10526a7d0aa8910729b6036ee51942e05b71abf6/compiler/src/dotty/tools/dotc/reporting/Reporter.scala). Enables calls such as `ctx.log`, `ctx.error` etc. To enable, run dotc with `-Ylog:typer` option.

tests/pos-special/typeclass-scaling.scala

@@ -3,7 +3,7 @@ import scala.annotation.tailrec
 
 // The following command:
 //
-//     sc typeclass-scaling.scala -Xmax-inlines 100 -Xprint:front -color:never -pagewidth 1000 >& x
+//     sc typeclass-scaling.scala -Xmax-inlines 100 -Xprint:typer -color:never -pagewidth 1000 >& x
 //
 // produces an output file with `wc` measures (lines/words/chars):
 //

tests/pos/implicits2.scala

@@ -1,6 +1,6 @@
 /* Compile with
 
-    dotc implicits2.scala -Xprint:front -Xprint-types -verbose
+    dotc implicits2.scala -Xprint:typer -Xprint-types -verbose
 
     and verify that the inserted wrapString comes from Predef. You should see
 

tests/pos/printbounds.scala

@@ -5,7 +5,7 @@ class Test {
 
   val x: Tree[_] = ???
 
-  val y = x // With -Xprint:front this should print  val x: Tree[_] = x
+  val y = x // With -Xprint:typer this should print  val x: Tree[_] = x
             // used to print Tree[Nothing], which is confusing.
 
 }