Fix Space parsing of type casts in Scala (#7306)

Author: greg-at-moderne

rewrite-scala/src/main/java/org/openrewrite/scala/ScalaPrinter.java

@@ -34,6 +34,7 @@
 import org.openrewrite.scala.marker.SObject;
 import org.openrewrite.scala.marker.TypeProjection;
 import org.openrewrite.scala.marker.ScalaForLoop;
+import org.openrewrite.scala.marker.AsInstanceOfPrefix;
 import org.openrewrite.scala.marker.TypeAscription;
 import org.openrewrite.scala.marker.UnderscorePlaceholderLambda;
 import org.openrewrite.scala.tree.S;
@@ -882,6 +883,8 @@ public J visitTypeCast(J.TypeCast typeCast, PrintOutputCapture<P> p) {
         // Existing asInstanceOf handling
         beforeSyntax(typeCast, Space.Location.TYPE_CAST_PREFIX, p);
         visit(typeCast.getExpression(), p);
+        typeCast.getMarkers().findFirst(AsInstanceOfPrefix.class)
+                .ifPresent(sp -> visitSpace(sp.getPrefix(), Space.Location.LANGUAGE_EXTENSION, p));
         p.append(".asInstanceOf");
         if (typeCast.getClazz() instanceof J.ControlParentheses) {
             J.ControlParentheses<?> controlParens = (J.ControlParentheses<?>) typeCast.getClazz();

rewrite-scala/src/main/java/org/openrewrite/scala/marker/AsInstanceOfPrefix.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2026 the original author or authors.
+ * <p>
+ * Licensed under the Moderne Source Available License (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://docs.moderne.io/licensing/moderne-source-available-license
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.scala.marker;
+
+import lombok.Value;
+import lombok.With;
+import org.openrewrite.Tree;
+import org.openrewrite.java.tree.Space;
+import org.openrewrite.marker.Marker;
+
+import java.util.UUID;
+
+/**
+ * Stores the whitespace that appears before {@code .asInstanceOf} in Scala
+ * constructs like {@code expr.asInstanceOf[Type]} where the dot may be on a new line.
+ */
+@Value
+@With
+public class AsInstanceOfPrefix implements Marker {
+    UUID id;
+    Space prefix;
+
+    public static AsInstanceOfPrefix create(Space prefix) {
+        return new AsInstanceOfPrefix(Tree.randomId(), prefix);
+    }
+}

rewrite-scala/src/main/scala/org/openrewrite/scala/internal/ScalaTreeVisitor.scala

@@ -35,6 +35,7 @@ import org.openrewrite.scala.marker.BlockArgument
 import org.openrewrite.scala.marker.TypeAscription
 import org.openrewrite.scala.marker.UnderscorePlaceholderLambda
 import org.openrewrite.scala.marker.Curried
+import org.openrewrite.scala.marker.AsInstanceOfPrefix
 import org.openrewrite.scala.tree.S
 
 import java.util
@@ -4285,11 +4286,17 @@ class ScalaTreeVisitor(
             case e: Expression => e
             case _ => return visitUnknown(ta)
           }
-          
-          // Update cursor past ".asInstanceOf"
+
+          // Capture whitespace before ".asInstanceOf" (e.g., newline + indentation)
           val asInstanceOfEnd = sel.span.end
-          if (asInstanceOfEnd > cursor) {
+          val selectPrefix = if (asInstanceOfEnd > cursor) {
+            val between = source.substring(cursor, asInstanceOfEnd)
+            val dotPos = between.indexOf('.')
+            val sp = if (dotPos > 0) Space.format(between.substring(0, dotPos)) else Space.EMPTY
             cursor = asInstanceOfEnd
+            sp
+          } else {
+            Space.EMPTY
           }
 
           // Now handle the type argument in brackets
@@ -4320,10 +4327,16 @@ class ScalaTreeVisitor(
             cursor = ta.span.end
           }
 
+          val markers = if (selectPrefix != Space.EMPTY) {
+            Markers.EMPTY.addIfAbsent(AsInstanceOfPrefix.create(selectPrefix))
+          } else {
+            Markers.EMPTY
+          }
+
           return new J.TypeCast(
             Tree.randomId(),
-            Space.EMPTY,  // TypeCast itself has no prefix - the space is handled by the variable initializer
-            Markers.EMPTY,
+            Space.EMPTY,
+            markers,
             new J.ControlParentheses[TypeTree](
               Tree.randomId(),
               spaceBeforeBracket,
@@ -4337,41 +4350,51 @@ class ScalaTreeVisitor(
         // Check if this is isInstanceOf
         if (sel.name.toString == "isInstanceOf" && ta.args.size == 1) {
           // This is a type check operation: obj.isInstanceOf[Type]
-          
+
           // Extract prefix
           val startPos = Math.max(0, ta.span.start - offsetAdjustment)
           val prefix = if (startPos > cursor && startPos <= source.length) {
             Space.format(source.substring(cursor, startPos))
           } else {
             Space.EMPTY
           }
-          
+
           // Update cursor to start of the expression (sel.qualifier)
           cursor = Math.max(0, sel.qualifier.span.start - offsetAdjustment)
-          
+
           // Visit the expression being checked
           val expr = visitTree(sel.qualifier) match {
             case e: Expression => e
             case _ => return visitUnknown(ta)
           }
-          
+
+          // Capture whitespace before ".isInstanceOf" (e.g., newline + indentation)
+          val isInstanceOfEnd = sel.span.end - offsetAdjustment
+          val exprAsInstanceOfPrefix = if (isInstanceOfEnd > cursor) {
+            val between = source.substring(cursor, isInstanceOfEnd)
+            val dotPos = between.indexOf('.')
+            if (dotPos > 0) Space.format(between.substring(0, dotPos)) else Space.EMPTY
+          } else {
+            Space.EMPTY
+          }
+
           // Update cursor to start of type argument
           cursor = Math.max(0, ta.args.head.span.start - offsetAdjustment)
-          
+
           // Visit the target type
           val clazz = visitTree(ta.args.head) match {
             case tt: TypeTree => tt
             case _ => return visitUnknown(ta)
           }
-          
+
           // Update cursor to the end of the TypeApply
           updateCursor(ta.span.end)
-          
+
           return new J.InstanceOf(
             Tree.randomId(),
             prefix,
             Markers.EMPTY,
-            JRightPadded.build(expr),
+            new JRightPadded(expr, exprAsInstanceOfPrefix, Markers.EMPTY),
             clazz,
             null, // pattern (not used in Scala)
             null  // type

rewrite-scala/src/test/java/org/openrewrite/scala/tree/InstanceOfTest.java

@@ -122,6 +122,20 @@ void instanceOfWithParentheses() {
         );
     }
 
+    @Test
+    void instanceOfOnNewLine() {
+        rewriteRun(
+            scala(
+                """
+                object Test {
+                  val x = Seq.empty
+                    .isInstanceOf[Seq[String]]
+                }
+                """
+            )
+        );
+    }
+
     @Test
     void multipleInstanceOfChecks() {
         rewriteRun(

rewrite-scala/src/test/java/org/openrewrite/scala/tree/TypeCastTest.java

@@ -122,6 +122,20 @@ void castWithParentheses() {
         );
     }
 
+    @Test
+    void castOnNewLine() {
+        rewriteRun(
+          scala(
+            """
+              object Test {
+                val x = Seq.empty
+                  .asInstanceOf[Seq[String]]
+              }
+              """
+          )
+        );
+    }
+
     @Test
     void castChain() {
         rewriteRun(