--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/api/JavacTrees.java	Fri Feb 15 05:32:36 2019 -0500
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/api/JavacTrees.java	Fri Feb 15 12:09:53 2019 +0100
@@ -1152,7 +1152,7 @@
         try {
             switch (kind) {
             case ERROR:
-                log.error(DiagnosticFlag.MULTIPLE, pos, Errors.ProcMessager(msg.toString()));
+                log.error(DiagnosticFlag.API, pos, Errors.ProcMessager(msg.toString()));
                 break;
 
             case WARNING:

--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/main/JavaCompiler.java	Fri Feb 15 05:32:36 2019 -0500
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/main/JavaCompiler.java	Fri Feb 15 12:09:53 2019 +0100
@@ -1014,7 +1014,11 @@
      * Parses a list of files.
      */
    public List<JCCompilationUnit> parseFiles(Iterable<JavaFileObject> fileObjects) {
-       if (shouldStop(CompileState.PARSE))
+       return parseFiles(fileObjects, false);
+   }
+
+   public List<JCCompilationUnit> parseFiles(Iterable<JavaFileObject> fileObjects, boolean force) {
+       if (!force && shouldStop(CompileState.PARSE))
            return List.nil();
 
         //parse all files

--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/processing/JavacMessager.java	Fri Feb 15 05:32:36 2019 -0500
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/processing/JavacMessager.java	Fri Feb 15 12:09:53 2019 +0100
@@ -34,6 +34,7 @@
 import com.sun.tools.javac.util.JCDiagnostic.DiagnosticFlag;
 import com.sun.tools.javac.tree.JCTree;
 import com.sun.tools.javac.tree.JCTree.*;
+import java.util.Set;
 import javax.lang.model.element.*;
 import javax.tools.JavaFileObject;
 import javax.tools.Diagnostic;
@@ -117,7 +118,7 @@
             switch (kind) {
             case ERROR:
                 errorCount++;
-                log.error(DiagnosticFlag.MULTIPLE, pos, Errors.ProcMessager(msg.toString()));
+                log.error(DiagnosticFlag.API, pos, Errors.ProcMessager(msg.toString()));
                 break;
 
             case WARNING:

--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java	Fri Feb 15 05:32:36 2019 -0500
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/processing/JavacProcessingEnvironment.java	Fri Feb 15 12:09:53 2019 +0100
@@ -35,6 +35,7 @@
 import java.nio.file.Path;
 import java.util.*;
 import java.util.Map.Entry;
+import java.util.function.Predicate;
 import java.util.regex.*;
 import java.util.stream.Collectors;
 
@@ -83,6 +84,7 @@
 import com.sun.tools.javac.util.DefinedBy.Api;
 import com.sun.tools.javac.util.Iterators;
 import com.sun.tools.javac.util.JCDiagnostic;
+import com.sun.tools.javac.util.JCDiagnostic.DiagnosticFlag;
 import com.sun.tools.javac.util.JavacMessages;
 import com.sun.tools.javac.util.List;
 import com.sun.tools.javac.util.Log;
@@ -1066,7 +1068,9 @@
             prev.newRound();
             this.genClassFiles = prev.genClassFiles;
 
-            List<JCCompilationUnit> parsedFiles = compiler.parseFiles(newSourceFiles);
+            //parse the generated files even despite errors reported so far, to eliminate
+            //recoverable errors related to the type declared in the generated files:
+            List<JCCompilationUnit> parsedFiles = compiler.parseFiles(newSourceFiles, true);
             roots = prev.roots.appendList(parsedFiles);
 
             // Check for errors after parsing
@@ -1233,15 +1237,17 @@
         }
 
         void showDiagnostics(boolean showAll) {
-            Set<JCDiagnostic.Kind> kinds = EnumSet.allOf(JCDiagnostic.Kind.class);
-            if (!showAll) {
-                // suppress errors, which are all presumed to be transient resolve errors
-                kinds.remove(JCDiagnostic.Kind.ERROR);
-            }
-            deferredDiagnosticHandler.reportDeferredDiagnostics(kinds);
+            deferredDiagnosticHandler.reportDeferredDiagnostics(showAll ? ACCEPT_ALL
+                                                                        : ACCEPT_NON_RECOVERABLE);
             log.popDiagnosticHandler(deferredDiagnosticHandler);
             compiler.setDeferredDiagnosticHandler(null);
         }
+        //where:
+            private final Predicate<JCDiagnostic> ACCEPT_NON_RECOVERABLE =
+                    d -> d.getKind() != JCDiagnostic.Kind.ERROR ||
+                         !d.isFlagSet(DiagnosticFlag.RECOVERABLE) ||
+                         d.isFlagSet(DiagnosticFlag.API);
+            private final Predicate<JCDiagnostic> ACCEPT_ALL = d -> true;
 
         /** Print info about this round. */
         private void printRoundInfo(boolean lastRound) {
@@ -1335,7 +1341,7 @@
             errorStatus = round.unrecoverableError();
             moreToDo = moreToDo();
 
-            round.showDiagnostics(errorStatus || showResolveErrors);
+            round.showDiagnostics(showResolveErrors);
 
             // Set up next round.
             // Copy mutable collections returned from filer.

--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/util/JCDiagnostic.java	Fri Feb 15 05:32:36 2019 -0500
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/util/JCDiagnostic.java	Fri Feb 15 12:09:53 2019 +0100
@@ -429,9 +429,9 @@
         RECOVERABLE,
         NON_DEFERRABLE,
         COMPRESSED,
-        /** Print multiple errors for same source locations.
+        /** Flag for diagnostics that were reported through API methods.
          */
-        MULTIPLE,
+        API,
         /** Flag for not-supported-in-source-X errors.
          */
         SOURCE_LEVEL;

--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/util/Log.java	Fri Feb 15 05:32:36 2019 -0500
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/util/Log.java	Fri Feb 15 12:09:53 2019 +0100
@@ -33,6 +33,7 @@
 import java.util.Map;
 import java.util.Queue;
 import java.util.Set;
+import java.util.function.Predicate;
 
 import javax.tools.DiagnosticListener;
 import javax.tools.JavaFileObject;
@@ -158,14 +159,14 @@
 
         /** Report all deferred diagnostics. */
         public void reportDeferredDiagnostics() {
-            reportDeferredDiagnostics(EnumSet.allOf(JCDiagnostic.Kind.class));
+            reportDeferredDiagnostics(d -> true);
         }
 
         /** Report selected deferred diagnostics. */
-        public void reportDeferredDiagnostics(Set<JCDiagnostic.Kind> kinds) {
+        public void reportDeferredDiagnostics(Predicate<JCDiagnostic> accepter) {
             JCDiagnostic d;
             while ((d = deferred.poll()) != null) {
-                if (kinds.contains(d.getKind()))
+                if (accepter.test(d))
                     prev.report(d);
             }
             deferred = null; // prevent accidental ongoing use
@@ -713,7 +714,7 @@
 
             case ERROR:
                 if (nerrors < MaxErrors &&
-                    (diagnostic.isFlagSet(DiagnosticFlag.MULTIPLE) ||
+                    (diagnostic.isFlagSet(DiagnosticFlag.API) ||
                      shouldReport(diagnostic))) {
                     writeDiagnostic(diagnostic);
                     nerrors++;

--- a/test/langtools/tools/javac/6304921/TestLog.java	Fri Feb 15 05:32:36 2019 -0500
+++ b/test/langtools/tools/javac/6304921/TestLog.java	Fri Feb 15 12:09:53 2019 +0100
@@ -76,7 +76,7 @@
         Set<DiagnosticFlag> defaultErrorFlags =
                 (Set<DiagnosticFlag>) defaultErrorFlagsField.get(diagnosticFactory);
 
-        defaultErrorFlags.add(DiagnosticFlag.MULTIPLE);
+        defaultErrorFlags.add(DiagnosticFlag.API);
 
         JavacFileManager.preRegister(context);
         ParserFactory pfac = ParserFactory.instance(context);

--- a/test/langtools/tools/javac/processing/6994946/SemanticErrorTest.2.out	Fri Feb 15 05:32:36 2019 -0500
+++ b/test/langtools/tools/javac/processing/6994946/SemanticErrorTest.2.out	Fri Feb 15 12:09:53 2019 +0100
@@ -1,3 +1,4 @@
+- compiler.err.proc.messager: Deliberate Error
+SemanticErrorTest.java:13:1: compiler.err.proc.messager: Deliberate Error on Trees
 SemanticErrorTest.java:13:46: compiler.err.repeated.interface
-- compiler.err.proc.messager: Deliberate Error
-2 errors
+3 errors

--- a/test/langtools/tools/javac/processing/6994946/TestProcessor.java	Fri Feb 15 05:32:36 2019 -0500
+++ b/test/langtools/tools/javac/processing/6994946/TestProcessor.java	Fri Feb 15 12:09:53 2019 +0100
@@ -27,13 +27,21 @@
 import javax.lang.model.element.*;
 import static javax.tools.Diagnostic.Kind.*;
 
+import com.sun.source.util.TreePath;
+import com.sun.source.util.Trees;
+
 public class TestProcessor extends JavacTestingAbstractProcessor {
    private int round = 0;
 
    public boolean process(Set<? extends TypeElement> annotations,
                   RoundEnvironment roundEnv) {
-        if (++round == 1)
+        if (++round == 1) {
             messager.printMessage(ERROR, "Deliberate Error");
+            Trees trees = Trees.instance(processingEnv);
+            TreePath elPath = trees.getPath(roundEnv.getRootElements().iterator().next());
+            trees.printMessage(ERROR, "Deliberate Error on Trees",
+                               elPath.getLeaf(), elPath.getCompilationUnit());
+        }
         return false;
    }
 }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/langtools/tools/javac/processing/GenerateAndError.java	Fri Feb 15 12:09:53 2019 +0100
@@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2019, 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
+ * @bug 8217381
+ * @summary Check error are convenient when AP generates a source file and
+ *          an error in the same round
+ * @library /tools/javac/lib
+ * @modules jdk.compiler
+ * @build JavacTestingAbstractProcessor GenerateAndError
+ * @compile/fail/ref=GenerateAndError.out -XDrawDiagnostics -processor GenerateAndError GenerateAndErrorTest.java
+ */
+
+import java.io.IOException;
+import java.io.Writer;
+import java.util.*;
+
+import javax.annotation.processing.*;
+import javax.lang.model.element.*;
+import javax.tools.Diagnostic.Kind;
+
+public class GenerateAndError extends JavacTestingAbstractProcessor {
+    int round = 0;
+    @Override
+    public boolean process(Set<? extends TypeElement> annotations, RoundEnvironment roundEnv) {
+        if (round++ == 0) {
+            try (Writer w = processingEnv.getFiler().createSourceFile("Extra").openWriter()) {
+                w.write("public class Extra {}");
+            } catch (IOException ex) {
+                throw new IllegalStateException(ex);
+            }
+            processingEnv.getMessager().printMessage(Kind.ERROR, "error");
+        }
+        return false;
+    }
+}

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/langtools/tools/javac/processing/GenerateAndError.out	Fri Feb 15 12:09:53 2019 +0100
@@ -0,0 +1,3 @@
+- compiler.err.proc.messager: error
+GenerateAndErrorTest.java:2:60: compiler.err.cant.resolve: kindname.class, ExtraExtra, , 
+2 errors

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/langtools/tools/javac/processing/GenerateAndErrorTest.java	Fri Feb 15 12:09:53 2019 +0100
@@ -0,0 +1,2 @@
+/* /nodynamiccopyright/ */
+public class GenerateAndErrorTest extends Extra implements ExtraExtra {}