Skip ProceedOnErrorTransTypes whenever possible

Keep track in the context of the files that have compile errors
so we only use ProceedOnErrorTransTypes on those and ignore it
for files without errors (as it can cause some other issues, eg
with XLargeTests being very slow)

Workaround for eclipse-jdtls#1008

org.eclipse.jdt.core.javac/src/org/eclipse/jdt/internal/javac/JavacCompiler.java

@@ -15,11 +15,14 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Queue;
+import java.util.Set;
 import java.util.stream.Stream;
 
+import javax.tools.Diagnostic;
 import javax.tools.DiagnosticListener;
 import javax.tools.JavaFileManager;
 import javax.tools.JavaFileObject;
@@ -54,10 +57,12 @@
 import com.sun.tools.javac.tree.JCTree.JCClassDecl;
 import com.sun.tools.javac.tree.JCTree.JCCompilationUnit;
 import com.sun.tools.javac.util.Context;
+import com.sun.tools.javac.util.Context.Key;
 import com.sun.tools.javac.util.Options;
 import com.sun.tools.javac.util.Pair;
 
 public class JavacCompiler extends Compiler {
+	public static final Key<Set<JavaFileObject>> FILES_WITH_ERRORS_KEY = new Key<>();
 	JavacConfig compilerConfig;
 	IProblemFactory problemFactory;
 
@@ -107,8 +112,13 @@ public void compile(ICompilationUnit[] sourceUnits) {
 		ProceedOnErrorTransTypes.preRegister(javacContext);
 		ProceedOnErrorGen.preRegister(javacContext);
 		JavacProblemConverter problemConverter = new JavacProblemConverter(this.compilerConfig.compilerOptions(), javacContext);
+		Set<JavaFileObject> sourceWithErrors = new HashSet<>();
+		javacContext.put(FILES_WITH_ERRORS_KEY, sourceWithErrors);
 		javacContext.put(DiagnosticListener.class, diagnostic -> {
 			if (diagnostic.getSource() instanceof JavaFileObject fileObject) {
+				if (diagnostic.getKind() == Diagnostic.Kind.ERROR) {
+					sourceWithErrors.add(fileObject);
+				}
 				JavacProblem javacProblem = problemConverter.createJavacProblem(diagnostic);
 				if (javacProblem != null) {
 					ICompilationUnit originalUnit = this.fileObjectToCUMap.get(fileObject);

org.eclipse.jdt.core.javac/src/org/eclipse/jdt/internal/javac/ProceedOnErrorTransTypes.java

@@ -13,8 +13,9 @@
 import com.sun.tools.javac.code.Symbol;
 import com.sun.tools.javac.code.Symbol.MethodSymbol;
 import com.sun.tools.javac.comp.TransTypes;
-import com.sun.tools.javac.tree.TreeInfo;
+import com.sun.tools.javac.tree.JCTree.JCClassDecl;
 import com.sun.tools.javac.tree.JCTree.JCMethodInvocation;
+import com.sun.tools.javac.tree.TreeInfo;
 import com.sun.tools.javac.util.Context;
 import com.sun.tools.javac.util.Context.Factory;
 
@@ -24,20 +25,46 @@ public static void preRegister(Context context) {
 		context.put(transTypesKey, (Factory<TransTypes>) c -> new ProceedOnErrorTransTypes(c));
 	}
 
+	private boolean needsProceedOnError;
+	private Context context;
+
 	protected ProceedOnErrorTransTypes(Context context) {
 		super(context);
+		this.context = context;
+	}
+
+	@Override
+	public void visitClassDef(JCClassDecl def) {
+		this.needsProceedOnError = hasErrors(def);
+		super.visitClassDef(def);
+		this.needsProceedOnError = false;
+	}
+
+	private boolean hasErrors(JCClassDecl def) {
+		return this.context.get(JavacCompiler.FILES_WITH_ERRORS_KEY).contains(def.sym.sourcefile);
 	}
 
 	@Override
 	public void visitApply(JCMethodInvocation tree) {
-		if (tree.type.isErroneous()) {
-			return;
-		}
-		tree.meth = translate(tree.meth, null);
-		Symbol meth = TreeInfo.symbol(tree.meth);
-		if (!(meth.baseSymbol() instanceof MethodSymbol)) {
-			//workaround: guard against ClassCastException when referencing non existing member
-			return;
+		if (this.needsProceedOnError) {
+			// The next lines of code should allow to generate
+			// classes with errors, but they are sometimes
+			// causing infinite processing for files that 
+			// have no errors (eg with XLargeTests).
+			// So at the moment we guard them by `needProceedOnError`
+			// but those lines must be considered fragile and made
+			// more bullet proof; concretely then need to work with
+			// XLargeTest.
+			// Cf https://github.com/eclipse-jdtls/eclipse-jdt-core-incubator/issues/1008
+			if (tree.type.isErroneous()) {
+				return;
+			}
+			tree.meth = translate(tree.meth, null);
+			Symbol meth = TreeInfo.symbol(tree.meth);
+			if (!(meth.baseSymbol() instanceof MethodSymbol)) {
+				//workaround: guard against ClassCastException when referencing non existing member
+				return;
+			}
 		}
 		super.visitApply(tree);
 	}