catch NullPointerException in typedTreeAt in signature help

scalameta · Dec 19, 2024 · af9753f · af9753f
1 parent a2e25a4
commit af9753f
Showing 1 changed file with 15 additions and 7 deletions.
diff --git a/mtags/src/main/scala-2/scala/meta/internal/pc/SignatureHelpProvider.scala b/mtags/src/main/scala-2/scala/meta/internal/pc/SignatureHelpProvider.scala
@@ -20,15 +20,23 @@ class SignatureHelpProvider(val compiler: MetalsGlobal) {
       cursor = cursor(params.offset(), params.text())
     )
     val pos = unit.position(params.offset())
-    typedTreeAt(pos)
-    val enclosingApply = new EnclosingApply(pos).find(unit.body)
-    val typedEnclosing = typedTreeAt(enclosingApply.pos)
-    new MethodCallTraverser(unit, pos)
-      .fromTree(typedEnclosing)
-      .map(toSignatureHelp)
-      .getOrElse(new SignatureHelp())
+    (for {
+      _ <- safeTypedTreeAt(pos)
+      enclosingApply = new EnclosingApply(pos).find(unit.body)
+      typedEnclosing <- safeTypedTreeAt(enclosingApply.pos)
+      encolsingCall <- new MethodCallTraverser(unit, pos).fromTree(
+        typedEnclosing
+      )
+    } yield toSignatureHelp(encolsingCall)) getOrElse new SignatureHelp()
   }
 
+  private def safeTypedTreeAt(pos: Position): Option[Tree] =
+    try {
+      Some(typedTreeAt(pos))
+    } catch {
+      case _: NullPointerException => None
+    }
+
   class EnclosingApply(pos: Position) extends Traverser {
     var last: Tree = EmptyTree
     def find(tree: Tree): Tree = {