From caf1c0a110aec1f29803bb4e9a0f3fdc26b98e79 Mon Sep 17 00:00:00 2001
From: Jaroslav Tulach <jaroslav.tulach@enso.org>
Date: Tue, 25 Apr 2023 14:56:02 +0200
Subject: [PATCH] Turn null into UnexpectedExpression when Union type is
 incomplete

---
 .../runtime/src/main/java/org/enso/compiler/TreeToIr.java | 3 +++
 .../test/java/org/enso/compiler/ErrorCompilerTest.java    | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/engine/runtime/src/main/java/org/enso/compiler/TreeToIr.java b/engine/runtime/src/main/java/org/enso/compiler/TreeToIr.java
index 13141b665bb6..67d7df1bd3ea 100644
--- a/engine/runtime/src/main/java/org/enso/compiler/TreeToIr.java
+++ b/engine/runtime/src/main/java/org/enso/compiler/TreeToIr.java
@@ -1084,6 +1084,9 @@ IR.Expression translateType(Tree tree, boolean insideTypeAscription) {
       }
       case Tree.OprApp app -> {
         var op = app.getOpr().getRight();
+        if (op == null) {
+          yield translateSyntaxError(app, IR$Error$Syntax$UnexpectedExpression$.MODULE$);
+        }
         yield switch (op.codeRepr()) {
           case "." -> {
             final Option<IdentifiedLocation> loc = getIdentifiedLocation(tree);
diff --git a/engine/runtime/src/test/java/org/enso/compiler/ErrorCompilerTest.java b/engine/runtime/src/test/java/org/enso/compiler/ErrorCompilerTest.java
index 4ea080cf5577..1d7172849ba6 100644
--- a/engine/runtime/src/test/java/org/enso/compiler/ErrorCompilerTest.java
+++ b/engine/runtime/src/test/java/org/enso/compiler/ErrorCompilerTest.java
@@ -192,6 +192,14 @@ public void malformedImport10() throws Exception {
     assertSingleSyntaxError(ir, IR$Error$Syntax$UnexpectedExpression$.MODULE$, "Unexpected expression", 0, 20);
   }
 
+  @Test
+  public void malformedTypeException() throws Exception {
+    var ir = parse("""
+    fan_out_to_columns : Table -> Text | Integer -> (Any -> Vector Any) -> | Nothing -> Problem_Behavior -> Table | Nothing
+    """);
+    assertSingleSyntaxError(ir, IR$Error$Syntax$UnexpectedExpression$.MODULE$, "Unexpected expression", 48, 119);
+  }
+
   @Test
   public void malformedImport11() throws Exception {
     var ir = parse("from import all");