Simplify context handling

 - Use only wildcard imports from Contexts
 - Use `(using Context)` throughout

Author: odersky

compiler/src/dotty/tools/backend/jvm/BCodeBodyBuilder.scala

@@ -19,7 +19,7 @@ import dotty.tools.dotc.core.Symbols._
 import dotty.tools.dotc.transform.Erasure
 import dotty.tools.dotc.transform.SymUtils._
 import dotty.tools.dotc.util.Spans._
-import dotty.tools.dotc.core.Contexts.{inContext, atPhase}
+import dotty.tools.dotc.core.Contexts._
 import dotty.tools.dotc.core.Phases._
 import dotty.tools.dotc.report
 

compiler/src/dotty/tools/backend/jvm/BCodeHelpers.scala

@@ -13,7 +13,7 @@ import dotty.tools.dotc.ast.tpd
 import dotty.tools.dotc.ast.Trees
 import dotty.tools.dotc.core.Annotations._
 import dotty.tools.dotc.core.Constants._
-import dotty.tools.dotc.core.Contexts.{Context, atPhase}
+import dotty.tools.dotc.core.Contexts._
 import dotty.tools.dotc.core.Phases._
 import dotty.tools.dotc.core.Decorators._
 import dotty.tools.dotc.core.Flags._
@@ -927,7 +927,7 @@ trait BCodeHelpers extends BCodeIdiomatic with BytecodeWriters {
     throw new RuntimeException(msg)
   }
 
-  private def compilingArray(using ctx: Context) =
+  private def compilingArray(using Context) =
     ctx.compilationUnit.source.file.name == "Array.scala"
 }
 

compiler/src/dotty/tools/backend/jvm/BTypesFromSymbols.scala

@@ -8,7 +8,7 @@ import scala.collection.mutable
 import scala.collection.generic.Clearable
 
 import dotty.tools.dotc.core.Flags._
-import dotty.tools.dotc.core.Contexts.{inContext, atPhase}
+import dotty.tools.dotc.core.Contexts._
 import dotty.tools.dotc.core.Phases._
 import dotty.tools.dotc.core.Symbols._
 import dotty.tools.dotc.core.Phases.Phase

compiler/src/dotty/tools/backend/jvm/CollectSuperCalls.scala

@@ -1,7 +1,7 @@
 package dotty.tools.backend.jvm
 
 import dotty.tools.dotc.ast.tpd
-import dotty.tools.dotc.core.Contexts.{Context, ctx}
+import dotty.tools.dotc.core.Contexts._
 import dotty.tools.dotc.core.Phases._
 import dotty.tools.dotc.core.Symbols._
 import dotty.tools.dotc.core.Flags.Trait

compiler/src/dotty/tools/backend/jvm/DottyBackendInterface.scala

@@ -197,7 +197,7 @@ object DottyBackendInterface {
    * True if the current compilation unit is of a primitive class (scala.Boolean et al).
    * Used only in assertions.
    */
-  def isCompilingPrimitive(using ctx: Context) = {
+  def isCompilingPrimitive(using Context) = {
     primitiveCompilationUnits(ctx.compilationUnit.source.file.name)
   }
 

compiler/src/dotty/tools/backend/jvm/GenBCode.scala

@@ -75,7 +75,7 @@ object GenBCode {
   val name: String = "genBCode"
 }
 
-class GenBCodePipeline(val int: DottyBackendInterface)(using ctx: Context) extends BCodeSyncAndTry {
+class GenBCodePipeline(val int: DottyBackendInterface)(using Context) extends BCodeSyncAndTry {
   import DottyBackendInterface.symExtensions
 
   private var tree: Tree = _

compiler/src/dotty/tools/backend/jvm/scalaPrimitives.scala

@@ -4,7 +4,7 @@ package backend.jvm
 import dotc.ast.Trees.Select
 import dotc.ast.tpd._
 import dotc.core._
-import Contexts.{Context, ctx}
+import Contexts._
 import Names.TermName, StdNames._
 import Types.{JavaArrayType, UnspecifiedErrorType, Type}
 import Symbols.{Symbol, NoSymbol}

compiler/src/dotty/tools/dotc/Bench.scala

@@ -1,7 +1,7 @@
 package dotty.tools
 package dotc
 
-import core.Contexts.{Context, ctx}
+import core.Contexts._
 import reporting.Reporter
 
 import scala.annotation.internal.sharable

compiler/src/dotty/tools/dotc/CompilationUnit.scala

@@ -2,7 +2,7 @@ package dotty.tools
 package dotc
 
 import core._
-import Contexts.{Context, ctx}
+import Contexts._
 import SymDenotations.ClassDenotation
 import Symbols._
 import util.{FreshNameCreator, SourceFile, NoSource}

compiler/src/dotty/tools/dotc/Driver.scala

@@ -5,7 +5,7 @@ import java.nio.file.{Files, Paths}
 import dotty.tools.FatalError
 import config.CompilerCommand
 import core.Comments.{ContextDoc, ContextDocstrings}
-import core.Contexts.{Context, ContextBase, inContext, ctx}
+import core.Contexts._
 import core.{MacroClassLoader, Mode, TypeError}
 import core.StdNames.nme
 import dotty.tools.dotc.ast.Positioned