Fix crash due to var x:T = _

Author: liufengyun

compiler/src/dotty/tools/dotc/transform/init/Summarization.scala

@@ -4,11 +4,13 @@ package init
 
 import core._
 import Contexts.Context
-import ast.tpd._
 import Decorators._
+import StdNames._
 import Symbols._
 import Constants.Constant
 import Types._
+
+import ast.tpd._
 import config.Printers.init
 import reporting.trace
 
@@ -26,6 +28,10 @@ object Summarization {
   def analyze(expr: Tree)(implicit env: Env): Summary =
   trace("summarizing " + expr.show, init, s => Summary.show(s.asInstanceOf[Summary])) {
     val summary: Summary = expr match {
+      case Ident(nme.WILDCARD) =>
+        // TODO:  disallow `var x: T = _`
+        Summary.empty
+
       case Ident(name) =>
         assert(name.isTermName, "type trees should not reach here")
         analyze(expr.tpe, expr)
@@ -229,7 +235,10 @@ object Summarization {
         val thisRef = ThisRef(thisTp.classSymbol.asClass)(source)
         val pot = SuperRef(thisRef, superTp.classSymbol.asClass)(source)
         Summary.empty + pot
-      }
+
+      case _ =>
+        throw new Exception("unexpected type: " + tp.show)
+    }
 
     if (env.isAlwaysInitialized(tp)) (Potentials.empty, summary._2)
     else summary

compiler/test/dotty/tools/dotc/CompilationTests.scala

@@ -299,10 +299,7 @@ class CompilationTests extends ParallelTesting {
   @Test def checkInitNeg: Unit = {
     implicit val testGroup: TestGroup = TestGroup("checkInit")
     val options = defaultOptions.and("-Ycheck-init", "-Xfatal-warnings")
-    aggregateTests(
-      compileFilesInDir("tests/init/neg/", options),
-      compileFilesInDir("tests/init/crash", options),
-    )
+    compileFilesInDir("tests/init/neg/", options)
   }.checkExpectedErrors()
 
   @Test def checkInitCrash: Unit = {