[javac] fix quickfix to implement inherited abstract methods

- add mapping for error id for missing abstract method implementations
- fixed an NPE that would prevent the error from being shown on
  anonymous classes
- fix binding logic for anonymous classes

example to try out: use the quickfix to add a stub implementation of
method() to the anonymous class:

```java
public class Parent {

  static interface IMethodable {
    void method();
  }

  public static void myMethod() {
    IMethodable methodable = new IMethodable() {
    };
    methodable.method();
  }

}
```

Future work: fix the diagnostic range on anonymous classes. We might
need access to the AST, since we ideally want to highlight `IMethodable`
from the constructor invocation.

Signed-off-by: David Thompson <[email protected]>

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

@@ -180,6 +180,16 @@ ITypeBinding resolveType(EnumDeclaration enumDecl) {
 		return null;
 	}
 
+	@Override
+	ITypeBinding resolveType(AnonymousClassDeclaration anonymousClassDecl) {
+		resolve();
+		JCTree javacNode = this.converter.domToJavac.get(anonymousClassDecl);
+		if (javacNode instanceof JCClassDecl jcClassDecl) {
+			return new JavacTypeBinding(jcClassDecl.type, this);
+		}
+		return null;
+	}
+
 	public IBinding getBinding(final Symbol owner, final com.sun.tools.javac.code.Type type) {
 		if (owner instanceof final PackageSymbol other) {
 			return new JavacPackageBinding(other, this);

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

@@ -246,12 +246,14 @@ private ExportsDirective convert(JCExports javac) {
 		res.setName(toName(javac.getPackageName()));
 		commonSettings(res, javac);
 		List<JCExpression> mods = javac.getModuleNames();
-		Iterator<JCExpression> it = mods.iterator();
-		while(it.hasNext()) {
-			JCExpression jcpe = it.next();
-			Expression e = convertExpression(jcpe);
-			if( e != null )
-				res.modules().add(e);
+		if (mods != null) {
+			Iterator<JCExpression> it = mods.iterator();
+			while(it.hasNext()) {
+				JCExpression jcpe = it.next();
+				Expression e = convertExpression(jcpe);
+				if( e != null )
+					res.modules().add(e);
+			}
 		}
 		return res;
 	}
@@ -729,14 +731,14 @@ private MethodDeclaration convertMethodDecl(JCMethodDecl javac, ASTNode parent)
 				retType = convertToType(unwrapDimensions(jcatt, dims));
 			}
 		}
-		
+
 		if( retType != null || isConstructor) {
 			if( this.ast.apiLevel != AST.JLS2_INTERNAL) {
 				res.setReturnType2(retType);
 			} else {
 				res.internalSetReturnType(retType);
 			}
-		} 
+		}
 
 		javac.getParameters().stream().map(this::convertVariableDeclaration).forEach(res.parameters()::add);
 
@@ -790,7 +792,7 @@ private MethodDeclaration convertMethodDecl(JCMethodDecl javac, ASTNode parent)
 		}
 		return res;
 	}
-	
+
 	private AbstractUnnamedTypeDeclaration findSurroundingTypeDeclaration(ASTNode parent) {
 		if( parent == null )
 			return null;
@@ -1415,7 +1417,7 @@ private AnonymousClassDeclaration createAnonymousClassDeclaration(JCClassDecl ja
 	private int countDimensions(JCArrayTypeTree tree) {
 		return countDimensionsAfterPosition(tree, 0);
 	}
-	
+
 	private int countDimensionsAfterPosition(JCArrayTypeTree tree, int pos) {
 		int ret = 0;
         JCTree elem = tree;
@@ -1426,7 +1428,7 @@ private int countDimensionsAfterPosition(JCArrayTypeTree tree, int pos) {
         }
         return ret;
 	}
-	
+
 	private JCTree unwrapDimensions(JCArrayTypeTree tree, int count) {
         JCTree elem = tree;
         while (elem != null && elem.hasTag(TYPEARRAY) && count > 0) {
@@ -1829,7 +1831,7 @@ private Statement convertStatement(JCStatement javac, ASTNode parent) {
 			if( jcAssert.getDetail() != null ) {
 				Expression det = convertExpression(jcAssert.getDetail());
 				if( det != null )
-					res.setMessage(det);			
+					res.setMessage(det);
 			}
 			return res;
 		}

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

@@ -132,7 +132,7 @@ private static org.eclipse.jface.text.Position getDiagnosticPosition(JCDiagnosti
 
 	private static org.eclipse.jface.text.Position getDiagnosticPosition(String name, int startPosition, JCDiagnostic jcDiagnostic)
 			throws IOException {
-		if (name != null) {
+		if (name != null && !name.isEmpty()) {
 			DiagnosticSource source = jcDiagnostic.getDiagnosticSource();
 			JavaFileObject fileObject = source.getFile();
 			CharSequence charContent = fileObject.getCharContent(true);
@@ -194,6 +194,7 @@ public static int toProblemId(Diagnostic<? extends JavaFileObject> diagnostic) {
 			case "compiler.err.cant.apply.symbol" -> convertInApplicableSymbols(diagnostic);
 			case "compiler.err.premature.eof" -> IProblem.ParsingErrorUnexpectedEOF; // syntax error
 			case "compiler.err.report.access" -> convertNotVisibleAccess(diagnostic);
+			case "compiler.err.does.not.override.abstract" -> IProblem.AbstractMethodMustBeImplemented;
 			case COMPILER_WARN_MISSING_SVUID -> IProblem.MissingSerialVersion;
 			case COMPILER_WARN_NON_SERIALIZABLE_INSTANCE_FIELD -> 99999999; // JDT doesn't have this diagnostic
 			case "compiler.err.ref.ambiguous" -> convertAmbiguous(diagnostic);