Groovy: add support for @memoize annotation

Author: greg-at-moderne

rewrite-groovy/src/main/java/org/openrewrite/groovy/GroovyParserVisitor.java

@@ -1180,6 +1180,13 @@ class B {                               class B {
                         } else {
                             body = bodyVisitor.doVisit(method.getCode());
                         }
+                    } else if (annotations.stream().anyMatch(a -> TypeUtils.isOfClassType(a.getAnnotationType().getType(), "groovy.transform.Memoized"))) {
+                        // The @Memoized AST transformation moves the original body into a synthetic
+                        // `memoizedMethodPriv$<name>` method (optionally prefixed with `_` on naming collisions)
+                        // and replaces the original method body with cache-lookup logic that has no source
+                        // positions. Find the private helper and visit its body so source positions align.
+                        MethodNode original = findMemoizedOriginalMethod(method);
+                        body = bodyVisitor.doVisit(original != null ? original.getCode() : method.getCode());
                     } else {
                         body = bodyVisitor.doVisit(method.getCode());
                     }
@@ -1206,6 +1213,22 @@ class B {                               class B {
         private <T> T pollQueue() {
             return (T) queue.poll();
         }
+
+        private @Nullable MethodNode findMemoizedOriginalMethod(MethodNode method) {
+            String suffix = "memoizedMethodPriv$" + method.getName();
+            for (MethodNode candidate : method.getDeclaringClass().getMethods()) {
+                String name = candidate.getName();
+                int start = 0;
+                while (start < name.length() && name.charAt(start) == '_') {
+                    start++;
+                }
+                if (name.substring(start).equals(suffix) &&
+                        candidate.getParameters().length == method.getParameters().length) {
+                    return candidate;
+                }
+            }
+            return null;
+        }
     }
 
     private class RewriteGroovyVisitor extends CodeVisitorSupport {

rewrite-groovy/src/test/java/org/openrewrite/groovy/tree/AnnotationTest.java

@@ -39,6 +39,24 @@ void run() {}
         );
     }
 
+    @Test
+    void memoizedMethod() {
+        rewriteRun(
+          groovy(
+            """
+              import groovy.transform.Memoized
+
+              class Foo {
+                  @Memoized
+                  Object bar() {
+                      return null
+                  }
+              }
+              """
+          )
+        );
+    }
+
     @Test
     void simpleFQN() {
         rewriteRun(