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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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/*
 * @test
 * @bug 8324736
 * @summary Verify starting and ending source positions are not backwards
 * @modules jdk.compiler/com.sun.tools.javac.tree
 * @run main ReversedSourcePositions
 */

import com.sun.source.tree.CompilationUnitTree;
import com.sun.source.tree.Tree;
import com.sun.source.util.JavacTask;
import com.sun.source.util.TreeScanner;
import com.sun.tools.javac.tree.JCTree;

import java.io.IOException;
import java.net.URI;
import java.util.List;

import javax.tools.JavaCompiler;
import javax.tools.JavaFileObject;
import javax.tools.SimpleJavaFileObject;
import javax.tools.ToolProvider;

public class ReversedSourcePositions {

    public static void main(String... args) throws Exception {

        // Create test case source
        var source = new SimpleJavaFileObject(URI.create("file://T.java"), JavaFileObject.Kind.SOURCE) {
            @Override
            public CharSequence getCharContent(boolean ignoreEncodingErrors) throws IOException {
                return """
                    package errorpronecrash;
                    ;
                    public class ReproFile {}
                """;
            }
        };

        // Parse source
        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
        JavaCompiler.CompilationTask task = compiler.getTask(null, null, null, List.of(), List.of(), List.of(source));
        Iterable<? extends CompilationUnitTree> units = ((JavacTask)task).parse();

        // Look for reversed source positions
        JCTree.JCCompilationUnit unit = (JCTree.JCCompilationUnit)units.iterator().next();
        unit.accept(new TreeScanner<Void, Void>() {
            @Override
            public Void scan(Tree node, Void aVoid) {
                if (node instanceof JCTree tree) {
                    int start = tree.getStartPosition();
                    int end = tree.getEndPosition(unit.endPositions);
                    if (start >= end) {
                        throw new AssertionError(
                          String.format("[%d, %d] %s %s\n", start, end, tree.getKind(), tree));
                    }
                }
                return super.scan(node, aVoid);
            }
        }, null);
    }
}