From 8a61ff432543a29234193cd1f7c14abd3f3d31a0 Mon Sep 17 00:00:00 2001
From: Felix Mulder <felix.mulder@gmail.com>
Date: Wed, 2 Nov 2016 11:08:28 +0100
Subject: Move compiler and compiler tests to compiler dir

---
 .../src/dotty/tools/dotc/typer/ImportInfo.scala    | 117 +++++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 compiler/src/dotty/tools/dotc/typer/ImportInfo.scala

(limited to 'compiler/src/dotty/tools/dotc/typer/ImportInfo.scala')

diff --git a/compiler/src/dotty/tools/dotc/typer/ImportInfo.scala b/compiler/src/dotty/tools/dotc/typer/ImportInfo.scala
new file mode 100644
index 000000000..3aa289181
--- /dev/null
+++ b/compiler/src/dotty/tools/dotc/typer/ImportInfo.scala
@@ -0,0 +1,117 @@
+package dotty.tools
+package dotc
+package typer
+
+import ast.{tpd, untpd}
+import ast.Trees._
+import core._
+import util.SimpleMap
+import Symbols._, Names._, Denotations._, Types._, Contexts._, StdNames._, Flags._
+import Decorators.StringInterpolators
+
+object ImportInfo {
+  /** The import info for a root import from given symbol `sym` */
+  def rootImport(refFn: () => TermRef)(implicit ctx: Context) = {
+    val selectors = untpd.Ident(nme.WILDCARD) :: Nil
+    def expr = tpd.Ident(refFn())
+    def imp = tpd.Import(expr, selectors)
+    new ImportInfo(imp.symbol, selectors, isRootImport = true)
+  }
+}
+
+/** Info relating to an import clause
+ *  @param   sym        The import symbol defined by the clause
+ *  @param   selectors  The selector clauses
+ *  @param   rootImport true if this is one of the implicit imports of scala, java.lang
+ *                      or Predef in the start context, false otherwise.
+ */
+class ImportInfo(symf: => Symbol, val selectors: List[untpd.Tree], val isRootImport: Boolean = false)(implicit ctx: Context) {
+
+  lazy val sym = symf
+
+  /** The (TermRef) type of the qualifier of the import clause */
+  def site(implicit ctx: Context): Type = {
+    val ImportType(expr) = sym.info
+    expr.tpe
+  }
+
+  /** The names that are excluded from any wildcard import */
+  def excluded: Set[TermName] = { ensureInitialized(); myExcluded }
+
+  /** A mapping from renamed to original names */
+  def reverseMapping: SimpleMap[TermName, TermName] = { ensureInitialized(); myMapped }
+
+  /** The original names imported by-name before renaming */
+  def originals: Set[TermName] = { ensureInitialized(); myOriginals }
+
+  /** Does the import clause end with wildcard? */
+  def isWildcardImport = { ensureInitialized(); myWildcardImport }
+
+  private var myExcluded: Set[TermName] = null
+  private var myMapped: SimpleMap[TermName, TermName] = null
+  private var myOriginals: Set[TermName] = null
+  private var myWildcardImport: Boolean = false
+
+  /** Compute info relating to the selector list */
+  private def ensureInitialized(): Unit = if (myExcluded == null) {
+    myExcluded = Set()
+    myMapped = SimpleMap.Empty
+    myOriginals = Set()
+    def recur(sels: List[untpd.Tree]): Unit = sels match {
+      case sel :: sels1 =>
+        sel match {
+          case Thicket(Ident(name: TermName) :: Ident(nme.WILDCARD) :: Nil) =>
+            myExcluded += name
+          case Thicket(Ident(from: TermName) :: Ident(to: TermName) :: Nil) =>
+            myMapped = myMapped.updated(to, from)
+            myExcluded += from
+            myOriginals += from
+          case Ident(nme.WILDCARD) =>
+            myWildcardImport = true
+          case Ident(name: TermName) =>
+            myMapped = myMapped.updated(name, name)
+            myOriginals += name
+        }
+        recur(sels1)
+      case nil =>
+    }
+    recur(selectors)
+  }
+
+  /** The implicit references imported by this import clause */
+  def importedImplicits: List[TermRef] = {
+    val pre = site
+    if (isWildcardImport) {
+      val refs = pre.implicitMembers
+      if (excluded.isEmpty) refs
+      else refs filterNot (ref => excluded contains ref.name.toTermName)
+    } else
+      for {
+        renamed <- reverseMapping.keys
+        denot <- pre.member(reverseMapping(renamed)).altsWith(_ is Implicit)
+      } yield TermRef.withSigAndDenot(pre, renamed, denot.signature, denot)
+  }
+
+  /** The root import symbol hidden by this symbol, or NoSymbol if no such symbol is hidden.
+   *  Note: this computation needs to work even for un-initialized import infos, and
+   *  is not allowed to force initialization.
+   */
+  lazy val hiddenRoot: Symbol = {
+    val sym = site.termSymbol
+    def hasMaskingSelector = selectors exists {
+      case Thicket(_ :: Ident(nme.WILDCARD) :: Nil) => true
+      case _ => false
+    }
+    if ((defn.RootImportTypes exists (_.symbol == sym)) && hasMaskingSelector) sym else NoSymbol
+  }
+
+  override def toString = {
+    val siteStr = site.show
+    val exprStr = if (siteStr endsWith ".type") siteStr dropRight 5 else siteStr
+    val selectorStr = selectors match {
+      case Ident(name) :: Nil => name.show
+      case _ => "{...}"
+    }
+    i"import $exprStr.$selectorStr"
+  }
+}
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