Merge pull request #10302 from som-snytt/issue/12726-CME-unit-checks

Avoid exception in post-typer checks
scala · Mar 16, 2023 · 36da1b3 · 36da1b3
2 parents 34e01b4 + d9ec261
commit 36da1b3
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Showing 2 changed files with 19 additions and 17 deletions.
diff --git a/src/compiler/scala/tools/nsc/CompilationUnits.scala b/src/compiler/scala/tools/nsc/CompilationUnits.scala
@@ -14,8 +14,7 @@ package scala.tools.nsc
 
 import scala.annotation.nowarn
 import scala.reflect.internal.util.{FreshNameCreator, NoSourceFile, SourceFile}
-import scala.collection.mutable
-import scala.collection.mutable.{LinkedHashSet, ListBuffer}
+import scala.collection.mutable, mutable.ArrayDeque
 
 trait CompilationUnits { global: Global =>
 
@@ -127,9 +126,9 @@ trait CompilationUnits { global: Global =>
     val transformed = new mutable.AnyRefMap[Tree, Tree]
 
     /** things to check at end of compilation unit */
-    val toCheck = new ListBuffer[CompilationUnit.ToCheck]
-    private[nsc] def addPostUnitCheck(check: CompilationUnit.ToCheckAfterUnit): Unit = toCheck += check
-    private[nsc] def addPostTyperCheck(check: CompilationUnit.ToCheckAfterTyper): Unit = toCheck += check
+    val toCheck = ArrayDeque.empty[CompilationUnit.ToCheck]
+    private[nsc] def addPostUnitCheck(check: CompilationUnit.ToCheckAfterUnit): Unit = toCheck.append(check)
+    private[nsc] def addPostTyperCheck(check: CompilationUnit.ToCheckAfterTyper): Unit = toCheck.append(check)
 
     /** The features that were already checked for this unit */
     var checkedFeatures = Set[Symbol]()
@@ -144,7 +143,7 @@ trait CompilationUnits { global: Global =>
     def targetPos: Position = NoPosition
 
     /** For sbt compatibility (https://github.com/scala/scala/pull/4588) */
-    val icode: LinkedHashSet[icodes.IClass] = new LinkedHashSet
+    val icode: mutable.LinkedHashSet[icodes.IClass] = new mutable.LinkedHashSet
 
     /** Is this about a .java source file? */
     val isJava: Boolean = source.isJava
@@ -153,8 +152,8 @@ trait CompilationUnits { global: Global =>
   }
 
   object CompilationUnit {
-    sealed trait ToCheck
-    trait ToCheckAfterUnit extends ToCheck { def apply(): Unit }
-    trait ToCheckAfterTyper extends ToCheck { def apply(): Unit }
+    sealed trait ToCheck { def apply(): Unit }
+    trait ToCheckAfterUnit extends ToCheck
+    trait ToCheckAfterTyper extends ToCheck
   }
 }
diff --git a/src/compiler/scala/tools/nsc/typechecker/Analyzer.scala b/src/compiler/scala/tools/nsc/typechecker/Analyzer.scala
@@ -13,7 +13,7 @@
 package scala.tools.nsc
 package typechecker
 
-import scala.collection.mutable.ListBuffer
+import scala.collection.mutable.ArrayDeque
 
 /** Defines the sub-components for the namer, packageobjects, and typer phases.
  */
@@ -100,7 +100,8 @@ trait Analyzer extends AnyRef
       // Lacking a better fix, we clear it here (before the phase is created, meaning for each
       // compiler run). This is good enough for the resident compiler, which was the most affected.
       undoLog.clear()
-      private val toCheckAfterTyper = new ListBuffer[CompilationUnit.ToCheckAfterTyper]
+      private val toCheckAfterTyper = ArrayDeque.empty[CompilationUnit.ToCheckAfterTyper]
+      def addCheckAfterTyper(check: CompilationUnit.ToCheckAfterTyper): Unit = toCheckAfterTyper.append(check)
       override def run(): Unit = {
         val start = if (settings.areStatisticsEnabled) statistics.startTimer(statistics.typerNanos) else null
         global.echoPhaseSummary(this)
@@ -111,8 +112,8 @@ trait Analyzer extends AnyRef
           undoLog.clear()
         }
         finishComputeParamAlias()
-        for (work <- toCheckAfterTyper) work()
-        toCheckAfterTyper.clear()
+        try while (toCheckAfterTyper.nonEmpty) toCheckAfterTyper.removeHead().apply()
+        finally toCheckAfterTyper.clearAndShrink()
         // defensive measure in case the bookkeeping in deferred macro expansion is buggy
         clearDelayed()
         if (settings.areStatisticsEnabled) statistics.stopTimer(statistics.typerNanos, start)
@@ -123,9 +124,11 @@ trait Analyzer extends AnyRef
           unit.body = typer.typed(unit.body)
           // interactive typed may finish by throwing a `TyperResult`
           if (!settings.Youtline.value) {
-            unit.toCheck foreach {
-              case now: CompilationUnit.ToCheckAfterUnit => now()
-              case later: CompilationUnit.ToCheckAfterTyper => toCheckAfterTyper += later
+            while (unit.toCheck.nonEmpty) {
+              unit.toCheck.removeHead() match {
+                case now: CompilationUnit.ToCheckAfterUnit => now()
+                case later: CompilationUnit.ToCheckAfterTyper => addCheckAfterTyper(later)
+              }
             }
             if (!settings.isScaladoc && settings.warnUnusedImport)
               warnUnusedImports(unit)
@@ -135,7 +138,7 @@ trait Analyzer extends AnyRef
         }
         finally {
           runReporting.reportSuspendedMessages(unit)
-          unit.toCheck.clear()
+          unit.toCheck.clearAndShrink()
         }
       }
     }