Fix error popups when class extends itself

Mostly null checks in bindings,
plus override type translation to prevent trying to access the broken
class.

Fixes #919

Signed-off-by: David Thompson <davthomp@redhat.com>

org.eclipse.jdt.core.javac/src/org/eclipse/jdt/core/dom/JavacBindingResolver.java

@@ -157,6 +157,9 @@ public JavacMethodBinding getMethodBinding(MethodType methodType, MethodSymbol s
 		}
 
 		public JavacMethodBinding getMethodBinding(MethodType methodType, MethodSymbol methodSymbol, com.sun.tools.javac.code.Type parentType, boolean isDeclaration) {
+			if (methodSymbol.owner == null || methodSymbol.owner.type == com.sun.tools.javac.code.Type.noType) {
+				return null;
+			}
 			JavacMethodBinding newInstance = new JavacMethodBinding(methodType, methodSymbol, parentType, JavacBindingResolver.this, false, isDeclaration) { };
 			return insertAndReturn(newInstance);
 		}
@@ -329,7 +332,7 @@ public JavacTypeVariableBinding getTypeVariableBinding(TypeVar typeVar) {
 		//
 		private Map<String, JavacVariableBinding> variableBindings = new HashMap<>();
 		public JavacVariableBinding getVariableBinding(VarSymbol varSymbol) {
-			if (varSymbol == null) {
+			if (varSymbol == null || varSymbol.owner == null || varSymbol.owner.type == com.sun.tools.javac.code.Type.noType) {
 				return null;
 			}
 			JavacVariableBinding newInstance = new JavacVariableBinding(varSymbol, JavacBindingResolver.this) { };
@@ -357,8 +360,8 @@ public IBinding getBinding(final Symbol owner, final com.sun.tools.javac.code.Ty
 			if (recoveredSymbol != null) {
 				return getBinding(recoveredSymbol, recoveredSymbol.type);
 			}
-			if (type instanceof ErrorType || owner.owner == null || owner.owner.type == com.sun.tools.javac.code.Type.noType) {
-				if (type.getOriginalType() instanceof MethodType missingMethodType) {
+			if (type instanceof ErrorType) {
+				if (type != null && type.getOriginalType() instanceof MethodType missingMethodType) {
 					return getErrorMethodBinding(missingMethodType, owner);
 				}
 			}

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

@@ -13,10 +13,10 @@
 import static com.sun.tools.javac.jvm.ByteCodes.athrow;
 
 import com.sun.tools.javac.code.Kinds.Kind;
+import com.sun.tools.javac.code.Type;
 import com.sun.tools.javac.code.Type.ErrorType;
 import com.sun.tools.javac.comp.Attr;
 import com.sun.tools.javac.jvm.Gen;
-import com.sun.tools.javac.tree.TreeMaker;
 import com.sun.tools.javac.tree.JCTree.JCArrayAccess;
 import com.sun.tools.javac.tree.JCTree.JCAssign;
 import com.sun.tools.javac.tree.JCTree.JCErroneous;
@@ -27,6 +27,7 @@
 import com.sun.tools.javac.tree.JCTree.JCLiteral;
 import com.sun.tools.javac.tree.JCTree.JCMethodInvocation;
 import com.sun.tools.javac.tree.JCTree.JCNewClass;
+import com.sun.tools.javac.tree.TreeMaker;
 import com.sun.tools.javac.util.Context;
 import com.sun.tools.javac.util.List;
 import com.sun.tools.javac.util.Names;
@@ -93,7 +94,7 @@ public void visitNewClass(JCNewClass tree) {
 
 	@Override
 	public void visitApply(JCMethodInvocation tree) {
-		if (tree.type.isErroneous()) {
+		if (tree.type.isErroneous() || !(tree.meth.type instanceof Type.MethodType)) {
 			visitErroneous(null);
 		} else {
 			super.visitApply(tree);
@@ -111,7 +112,7 @@ public void visitSelect(JCFieldAccess tree) {
 
 	@Override
 	public void visitExec(JCExpressionStatement tree) {
-		if (tree.expr == null || tree.expr instanceof JCErroneous || tree.expr.type.isErroneous()) {
+		if (tree.expr == null || tree.expr instanceof JCErroneous || tree.expr.type.isErroneous() || tree.expr.type instanceof Type.UnknownType) {
 			visitErroneous(null);
 		} else {
 			super.visitExec(tree);

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

@@ -12,9 +12,13 @@
 
 import com.sun.tools.javac.code.Symbol;
 import com.sun.tools.javac.code.Symbol.MethodSymbol;
+import com.sun.tools.javac.code.Type.ClassType;
+import com.sun.tools.javac.code.Type.ErrorType;
 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.JCIdent;
 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;
 
@@ -37,9 +41,31 @@ public void visitApply(JCMethodInvocation tree) {
 		Symbol meth = TreeInfo.symbol(tree.meth);
 		if (!(meth.baseSymbol() instanceof MethodSymbol)) {
 			//workaround: guard against ClassCastException when referencing non existing member
+			result = tree;
 			return;
 		}
 		super.visitApply(tree);
 	}
+
+	@Override
+	public void visitClassDef(JCClassDecl tree) {
+		if (tree.sym.type.isErroneous() && tree.sym.type instanceof ErrorType errorType) {
+			// HACK: likely a cyclic dependency chain. Remove the inheritance and replace the symbol's type with a boring one.
+			tree.extending = null;
+			ClassType classType = new ClassType(errorType.getEnclosingType(), com.sun.tools.javac.util.List.nil(), tree.sym);
+			tree.sym.type = classType;
+			tree.setType(classType);
+		}
+		super.visitClassDef(tree);
+	}
+
+	@Override
+	public void visitIdent(JCIdent tree) {
+		if (tree.sym.type.getEnclosingType() == null) {
+			result = tree;
+			return;
+		}
+		super.visitIdent(tree);
+	}
 
 }