Don't generate signatures for backticked-names

Author: Duhemm

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

@@ -838,17 +838,17 @@ object Erasure {
       }
     }
 
-    // TODO: Find how to encode names
-    def sanitizeName(name: Name): String =
-      name.toString.replaceAll("""\!""", """\$bang""")
-        .replaceAll("""=""", """\$eq""")
-        .replaceAll("""~""", """\$tilde""")
-        .replace("-", "$minus")
-        .replace("+", "$plus")
-        .replace(">", "$greater")
-        .replace("<", "$less")
-        .replace(":", "$colon")
-        .replace(";", "$u003B")
+    // This will reject any name that has characters that cannot appear in
+    // names on the JVM. Interop with Java is not guaranteed for those, so we
+    // dont need to generate signatures for them.
+    def sanitizeName(name: Name): String = {
+      val nameString = name.mangledString
+      if (nameString.forall(c => c == '.' || Character.isJavaIdentifierPart(c))) {
+        nameString
+      } else {
+        throw new UnknownSig
+      }
+    }
 
     // Anything which could conceivably be a module (i.e. isn't known to be
     // a type parameter or similar) must go through here or the signature is

tests/generic-java-signatures/invalidNames.check

@@ -0,0 +1,10 @@
+class Foo[`![]:;!!` <: java.util.Date]
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val tParams = classOf[Foo[_]].getTypeParameters()
+    tParams.foreach { tp =>
+      println(tp.getName + " <: " + tp.getBounds.map(_.getTypeName).mkString(", "))
+    }
+  }
+}

tests/generic-java-signatures/invalidNames.scala

@@ -0,0 +1 @@
+$bang$bang$bang <: java.util.Date

tests/generic-java-signatures/mangledNames.check

@@ -0,0 +1,10 @@
+class Foo[`!!!` <: java.util.Date]
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val tParams = classOf[Foo[_]].getTypeParameters()
+    tParams.foreach { tp =>
+      println(tp.getName + " <: " + tp.getBounds.map(_.getTypeName).mkString(", "))
+    }
+  }
+}