Making annotation processing work with patterns. (openjdk#6)

Author: lahodaj

src/jdk.compiler/share/classes/com/sun/tools/javac/comp/MemberEnter.java

@@ -103,6 +103,7 @@ protected MemberEnter(Context context) {
     Type signature(MethodSymbol msym,
                    List<JCTypeParameter> typarams,
                    List<JCVariableDecl> params,
+                   List<JCVariableDecl> bindings,
                    JCTree res,
                    JCVariableDecl recvparam,
                    List<JCExpression> thrown,
@@ -119,6 +120,18 @@ Type signature(MethodSymbol msym,
             argbuf.append(l.head.vartype.type);
         }
 
+        // Enter and bindings.
+        ListBuffer<Type> bindingsbuf = null;
+
+        if (bindings != null) {
+            bindingsbuf = new ListBuffer<>();
+
+            for (List<JCVariableDecl> l = bindings; l.nonEmpty(); l = l.tail) {
+                memberEnter(l.head, env);
+                bindingsbuf.append(l.head.vartype.type);
+            }
+        }
+
         // Attribute result type, if one is given.
         Type restype = res == null ? syms.voidType : attr.attribType(res, env);
 
@@ -147,6 +160,10 @@ Type signature(MethodSymbol msym,
                                     restype,
                                     thrownbuf.toList(),
                                     syms.methodClass);
+        if (bindings != null) {
+            mtype.bindingtypes = bindingsbuf.toList();
+        }
+
         mtype.recvtype = recvtype;
 
         return tvars.isEmpty() ? mtype : new ForAll(tvars, mtype);
@@ -197,14 +214,10 @@ public void visitMethodDef(JCMethodDecl tree) {
         DiagnosticPosition prevLintPos = deferredLintHandler.setPos(tree.pos());
         try {
             // Compute the method type
-            Type t = signature(m, tree.typarams, tree.params,
+            Type t = signature(m, tree.typarams, tree.params, tree.bindings,
                                tree.restype, tree.recvparam,
                                tree.thrown,
                                localEnv);
-            if (t instanceof MethodType mt && m.isPattern()) {
-                mt.bindingtypes = mt.argtypes;
-                mt.argtypes = List.nil();
-            }
             m.type = t;
         } finally {
             deferredLintHandler.setPos(prevLintPos);
@@ -222,20 +235,24 @@ public void visitMethodDef(JCMethodDecl tree) {
             params.append(Assert.checkNonNull(param.sym));
         }
 
-        if (m.isPattern()) {
-            m.bindings = params.toList();
-            m.params = List.nil();
-            tree.bindings = tree.params;
-            tree.params = List.nil();
-        } else {
-            m.params = params.toList();
-            m.bindings = List.nil();
-        }
+        m.params = params.toList();
 
         // mark the method varargs, if necessary
         if (lastParam != null && (lastParam.mods.flags & Flags.VARARGS) != 0)
             m.flags_field |= Flags.VARARGS;
 
+        // Set m.bindings
+        ListBuffer<VarSymbol> bindings = new ListBuffer<>();
+
+        if (tree.bindings != null) {
+            for (List<JCVariableDecl> l = tree.bindings; l.nonEmpty(); l = l.tail) {
+                JCVariableDecl binding = l.head;
+                bindings.append(Assert.checkNonNull(binding.sym));
+            }
+        }
+
+        m.bindings = bindings.toList();
+
         localEnv.info.scope.leave();
         if (chk.checkUnique(tree.pos(), m, enclScope)) {
         enclScope.enter(m);

src/jdk.compiler/share/classes/com/sun/tools/javac/parser/JavacParser.java

@@ -5086,10 +5086,16 @@ protected JCTree methodDeclaratorRest(int pos,
                 }
             }
 
+            boolean isPattern = (mods.flags & PATTERN) != 0;
             JCMethodDecl result =
                     toP(F.at(pos).MethodDef(mods, name, type, typarams,
-                                            receiverParam, params, thrown,
+                                            receiverParam, isPattern ? List.nil() : params, thrown,
                                             body, defaultValue));
+
+            if (isPattern) {
+                result.bindings = params;
+            }
+
             attach(result, dc);
             return result;
         } finally {

test/langtools/tools/javac/patterns/declarations/AnnotationProcessing.java

@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2024, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @summary Verify that annotation processing works with patterns.
+ * @library /tools/lib
+ * @modules jdk.compiler/com.sun.tools.javac.api
+ *          jdk.compiler/com.sun.tools.javac.main
+ * @build toolbox.TestRunner toolbox.ToolBox AnnotationProcessing
+ * @run main AnnotationProcessing
+ */
+
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.Set;
+
+import javax.annotation.processing.AbstractProcessor;
+import javax.annotation.processing.RoundEnvironment;
+import javax.annotation.processing.SupportedAnnotationTypes;
+import javax.lang.model.SourceVersion;
+import javax.lang.model.element.TypeElement;
+import toolbox.JavacTask;
+import toolbox.TestRunner;
+import toolbox.TestRunner.Test;
+import toolbox.ToolBox;
+
+public class AnnotationProcessing extends TestRunner {
+
+    public static void main(String... args) throws Exception {
+        new AnnotationProcessing().runTests(m -> new Object[] { Paths.get(m.getName()) });
+    }
+
+    private final ToolBox tb = new ToolBox();
+
+    public AnnotationProcessing() {
+        super(System.err);
+    }
+
+    @Test
+    public void testErrorsAfter(Path outerBase) throws Exception {
+        Path src = outerBase.resolve("src");
+        tb.writeJavaFiles(src,
+                          """
+                          public class T {
+                              public pattern T(int i) {
+                                  match T(0);
+                              }
+                          }
+                          """);
+        Path classes = outerBase.resolve("classes");
+        Files.createDirectories(classes);
+        new JavacTask(tb)
+            .options("-processor", "AnnotationProcessing$P",
+                     "-processorpath", System.getProperty("test.classes"),
+                     "--enable-preview", "--source", System.getProperty("java.specification.version"))
+            .outdir(classes.toString())
+            .files(tb.findJavaFiles(src))
+            .run()
+            .writeAll();
+    }
+
+    @SupportedAnnotationTypes("*")
+    public static class P extends AbstractProcessor {
+        @Override
+        public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
+            return false;
+        }
+
+        @Override
+        public SourceVersion getSupportedSourceVersion() {
+            return SourceVersion.latest();
+        }
+    }
+
+}