Move the patmat phase after superaccessors

In dotty, pickling trees into Tasty is done after the super accessors
phase but before the pattern matching phase. But in scalac, patmat comes
before superaccessors. This commit simply swaps these phases around,
thus making it possible to write a compiler plugin for scalac that
produces a Tasty file from the output of the superaccessors phase.

(cherry picked from commit 7ad3a2e)

Author: smarter

src/compiler/scala/tools/nsc/Global.scala

@@ -473,23 +473,25 @@ class Global(var currentSettings: Settings, reporter0: Reporter)
   // phaseName = "patmat"
   object patmat extends {
     val global: Global.this.type = Global.this
-    val runsAfter = List("typer")
+    // patmat does not need to run before the superaccessors phase, because
+    // patmat never emits `this.x` where `x` is a ParamAccessor.
+    // (However, patmat does need to run before outer accessors generation).
+    val runsAfter = List("superaccessors")
     val runsRightAfter = None
-    // patmat doesn't need to be right after typer, as long as we run before superaccessors
-    // (sbt does need to run right after typer, so don't conflict)
   } with PatternMatching
 
   // phaseName = "superaccessors"
   object superAccessors extends {
     val global: Global.this.type = Global.this
-    val runsAfter = List("patmat")
+    val runsAfter = List("typer")
+    // sbt needs to run right after typer, so don't conflict
     val runsRightAfter = None
   } with SuperAccessors
 
   // phaseName = "extmethods"
   object extensionMethods extends {
     val global: Global.this.type = Global.this
-    val runsAfter = List("superaccessors")
+    val runsAfter = List("patmat")
     val runsRightAfter = None
   } with ExtensionMethods
 
@@ -653,8 +655,8 @@ class Global(var currentSettings: Settings, reporter0: Reporter)
       analyzer.namerFactory   -> "resolve names, attach symbols to named trees",
       analyzer.packageObjects -> "load package objects",
       analyzer.typerFactory   -> "the meat and potatoes: type the trees",
-      patmat                  -> "translate match expressions",
       superAccessors          -> "add super accessors in traits and nested classes",
+      patmat                  -> "translate match expressions",
       extensionMethods        -> "add extension methods for inline classes",
       pickler                 -> "serialize symbol tables",
       refChecks               -> "reference/override checking, translate nested objects",

test/files/neg/t6446-additional.check

@@ -4,8 +4,8 @@
          namer   2  resolve names, attach symbols to named trees
 packageobjects   3  load package objects
          typer   4  the meat and potatoes: type the trees
-        patmat   5  translate match expressions
-superaccessors   6  add super accessors in traits and nested classes
+superaccessors   5  add super accessors in traits and nested classes
+        patmat   6  translate match expressions
     extmethods   7  add extension methods for inline classes
        pickler   8  serialize symbol tables
      refchecks   9  reference/override checking, translate nested objects

test/files/neg/t6446-missing.check

@@ -5,8 +5,8 @@ Error: unable to load class: t6446.Ploogin
          namer   2  resolve names, attach symbols to named trees
 packageobjects   3  load package objects
          typer   4  the meat and potatoes: type the trees
-        patmat   5  translate match expressions
-superaccessors   6  add super accessors in traits and nested classes
+superaccessors   5  add super accessors in traits and nested classes
+        patmat   6  translate match expressions
     extmethods   7  add extension methods for inline classes
        pickler   8  serialize symbol tables
      refchecks   9  reference/override checking, translate nested objects

test/files/neg/t6446-show-phases.check

@@ -4,8 +4,8 @@
          namer   2  resolve names, attach symbols to named trees
 packageobjects   3  load package objects
          typer   4  the meat and potatoes: type the trees
-        patmat   5  translate match expressions
-superaccessors   6  add super accessors in traits and nested classes
+superaccessors   5  add super accessors in traits and nested classes
+        patmat   6  translate match expressions
     extmethods   7  add extension methods for inline classes
        pickler   8  serialize symbol tables
      refchecks   9  reference/override checking, translate nested objects

test/files/neg/t7494-no-options.check

@@ -5,8 +5,8 @@ error: Error: ploogin takes no options
          namer   2  resolve names, attach symbols to named trees
 packageobjects   3  load package objects
          typer   4  the meat and potatoes: type the trees
-        patmat   5  translate match expressions
-superaccessors   6  add super accessors in traits and nested classes
+superaccessors   5  add super accessors in traits and nested classes
+        patmat   6  translate match expressions
     extmethods   7  add extension methods for inline classes
        pickler   8  serialize symbol tables
      refchecks   9  reference/override checking, translate nested objects

test/files/run/programmatic-main.check

@@ -4,8 +4,8 @@
          namer   2  resolve names, attach symbols to named trees
 packageobjects   3  load package objects
          typer   4  the meat and potatoes: type the trees
-        patmat   5  translate match expressions
-superaccessors   6  add super accessors in traits and nested classes
+superaccessors   5  add super accessors in traits and nested classes
+        patmat   6  translate match expressions
     extmethods   7  add extension methods for inline classes
        pickler   8  serialize symbol tables
      refchecks   9  reference/override checking, translate nested objects