Only run InlineCalls if the tree contains an inline call

Author: nicolasstucki

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

@@ -25,6 +25,11 @@ class CompilationUnit(val source: SourceFile) {
   /** Pickled TASTY binaries, indexed by class. */
   var pickled: Map[ClassSymbol, Array[Byte]] = Map()
 
+  /** Will be reset to `true` if `tpdTree` contains a call to an inline method. The information
+   *  is used in phase InlineCalls in order to avoid traversing an inline-less tree.
+   */
+  var containsInlineCalls: Boolean = false
+
   /** Will be reset to `true` if `untpdTree` contains `Quote` trees. The information
    *  is used in phase ReifyQuotes in order to avoid traversing a quote-less tree.
    */
@@ -48,20 +53,22 @@ object CompilationUnit {
     if (forceTrees) {
       val force = new Force
       force.traverse(unit1.tpdTree)
+      unit1.containsInlineCalls = force.containsInline
       unit1.containsQuotesOrSplices = force.containsQuotes
     }
     unit1
   }
 
   /** Force the tree to be loaded */
   private class Force extends TreeTraverser {
+    var containsInline = false
     var containsQuotes = false
     def traverse(tree: Tree)(implicit ctx: Context): Unit = {
       if (tree.symbol.isQuote)
         containsQuotes = true
       tree match {
         case _: tpd.RefTree | _: Trees.GenericApply[_] if Inliner.isInlineable(tree) =>
-          containsQuotes = true // May inline a quote
+          containsInline = true
         case _ =>
       }
       traverseChildren(tree)

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

@@ -5,6 +5,7 @@ import dotty.tools.dotc.ast.tpd
 import dotty.tools.dotc.core.Contexts._
 import dotty.tools.dotc.core.Phases.Phase
 import dotty.tools.dotc.core.Types.MethodicType
+import dotty.tools.dotc.transform.SymUtils._
 import dotty.tools.dotc.typer.{ConstFold, Inliner}
 
 /** β-reduce all calls to inline methods and preform constant folding */
@@ -14,7 +15,7 @@ class InlineCalls extends MacroTransform { thisPhase =>
   override def phaseName: String = InlineCalls.name
 
   override def run(implicit ctx: Context): Unit =
-    if (!ctx.settings.YnoInline.value) super.run
+    if (ctx.compilationUnit.containsInlineCalls && !ctx.settings.YnoInline.value) super.run
 
   override def transformPhase(implicit ctx: Context): Phase = thisPhase.next
 
@@ -31,6 +32,8 @@ class InlineCalls extends MacroTransform { thisPhase =>
         newTree.symbol.defTree = newTree // update tree set in PostTyper or set for inlined members
         newTree
       case _ =>
+        if (tree.symbol.isQuote || tree.symbol.isSplice)
+          ctx.compilationUnit.containsQuotesOrSplices = true
         ConstFold(super.transform(tree))
     }
   }

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

@@ -180,7 +180,7 @@ class PostTyper extends MacroTransform with IdentityDenotTransformer { thisPhase
 
     private def handleInlineCall(sym: Symbol)(implicit ctx: Context): Unit = {
       if (sym.is(Inline))
-        ctx.compilationUnit.containsQuotesOrSplices = true
+        ctx.compilationUnit.containsInlineCalls = true
     }
 
     private object dropInlines extends TreeMap {