Add test case.

Author: lidaisy

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

@@ -1353,13 +1353,11 @@ object Semantic:
 
       case closureDef(ddef) =>
         val rhs = ddef.getRhs
-        if rhs.isEmpty then Hot
-        else Fun(rhs, thisV, klass)
+        Fun(rhs, thisV, klass)
 
       case PolyFun(ddef) =>
         val rhs = ddef.getRhs
-        if rhs.isEmpty then Hot
-        else Fun(rhs, thisV, klass)
+        Fun(rhs, thisV, klass)
 
       case Block(stats, expr) =>
         eval(stats, thisV, klass)
@@ -1414,7 +1412,6 @@ object Semantic:
         val rhs = vdef.getRhs
         eval(rhs, thisV, klass)
 
-
       case ddef : DefDef =>
         // local method
         Hot

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

@@ -263,6 +263,29 @@ class CompilationTests {
 
       tests.foreach(_.delete())
     }
+
+    /* This tests for errors in the program's TASTy trees.
+    * The test consists of three files: (a) v1/A, (b) v1/B, and (c) v0/A. (a) and (b) are
+    * compatible, but (b) and (c) are not. If (b) and (c) are compiled together, there should be
+    * an error when reading the files' TASTy trees. */
+    locally {
+      val tastyErrorGroup = TestGroup("checkInit/tasty-error")
+      val tastyErrorOptions = options.without("-Xfatal-warnings")
+
+      val a0 = defaultOutputDir + tastyErrorGroup + "/A/v0/A"
+      val a1 = defaultOutputDir + tastyErrorGroup + "/A/v1/A"
+      val b1 = defaultOutputDir + tastyErrorGroup + "/B/v1/B"
+      val a0b1 = a0 + ":" + b1
+
+      val tests = List(
+        compileFile("tests/init/tasty-error/v1/A.scala", tastyErrorOptions)(tastyErrorGroup),
+        compileFile("tests/init/tasty-error/v1/B.scala", tastyErrorOptions.withClasspath(a1))(tastyErrorGroup),
+        compileFile("tests/init/tasty-error/v0/A.scala", tastyErrorOptions)(tastyErrorGroup),
+      ).map(_.keepOutput.checkCompile())
+      compileFile("tests/init/tasty-error/Main.scala", tastyErrorOptions.withClasspath(a0b1))(tastyErrorGroup).expectFailure.checkCompile()
+
+      tests.foreach(_.delete())
+    }
   }
 
   // parallel backend tests

tests/init/tasty-error/Main.scala

@@ -0,0 +1 @@
+class Main extends B{}

tests/init/tasty-error/v0/A.scala

@@ -0,0 +1,3 @@
+class A {
+  def fail(a: Int, b: Int): Int = a
+}

tests/init/tasty-error/v1/A.scala

@@ -0,0 +1,3 @@
+class A {
+  def fail(a: Int): Int = a
+}

tests/init/tasty-error/v1/B.scala

@@ -0,0 +1,4 @@
+class B {
+  val a: A = new A
+  val x = a.fail(0)
+}