Fix resolving JavaElement for binary types/methods

* Special rules for when using a mock name for Javac (this could
probably be improved by getting ASTParser to pass through the actual
class name and resusing it)
* Use resolved types signatures from binding to retrieve method
reference
* Better signature for parameterized/generic types

Author: mickaelistria

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

@@ -112,6 +112,8 @@
  */
 public class JavacCompilationUnitResolver implements ICompilationUnitResolver {
 
+	public static final String MOCK_NAME_FOR_CLASSES = "whatever_InvalidNameWE_HOP3_n00ne_will_Ever_use_in_real_file.java";
+	
 	private final class ForwardDiagnosticsAsDOMProblems implements DiagnosticListener<JavaFileObject> {
 		public final Map<JavaFileObject, CompilationUnit> filesToUnits;
 		private final JavacProblemConverter problemConverter;
@@ -711,7 +713,7 @@ public Void visitClass(ClassTree node, Void p) {
 					sourceUnitPath = Path.of(lastSegment);
 				}
 				if( sourceUnitPath == null )
-					sourceUnitPath = Path.of(new File("whatever.java").toURI());
+					sourceUnitPath = Path.of(new File(MOCK_NAME_FOR_CLASSES).toURI());
 			} else {
 				sourceUnitPath = Path.of(unitFile.toURI());
 			}

…/internal/codeassist/SignatureUtils.java …eclipse/jdt/internal/SignatureUtils.javaorg.eclipse.jdt.core.javac/src/org/eclipse/jdt/internal/codeassist/SignatureUtils.java renamed to org.eclipse.jdt.core.javac/src/org/eclipse/jdt/internal/SignatureUtils.java org.eclipse.jdt.core.javac/src/org/eclipse/jdt/internal/codeassist/SignatureUtils.java renamed to org.eclipse.jdt.core.javac/src/org/eclipse/jdt/internal/SignatureUtils.java

@@ -8,10 +8,12 @@
  *
  * SPDX-License-Identifier: EPL-2.0
  *******************************************************************************/
-package org.eclipse.jdt.internal.codeassist;
+package org.eclipse.jdt.internal;
 
 import java.util.ArrayList;
 import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import org.eclipse.core.runtime.ILog;
 import org.eclipse.core.runtime.IProgressMonitor;
@@ -95,23 +97,54 @@ public static String createSignature(IType type) {
 	}
 
 	/**
-	 * Returns the signature of the given type binding.
+	 * Returns the signature of the given type binding as a character array.
 	 *
 	 * @param typeBinding the type binding to get the signature of
-	 * @return the signature of the given type binding
+	 * @return the signature of the given type binding as a character array
 	 */
-	public static String getSignature(ITypeBinding typeBinding) {
-		return SignatureUtils.getSignatureForTypeKey(typeBinding.getKey());
+	public static char[] getSignatureChar(ITypeBinding typeBinding) {
+		return SignatureUtils.getSignature(typeBinding).toCharArray();
 	}
 
 	/**
-	 * Returns the signature of the given type binding as a character array.
+	 * Returns the signature of the given type binding.
 	 *
 	 * @param typeBinding the type binding to get the signature of
-	 * @return the signature of the given type binding as a character array
+	 * @return the signature of the given type binding
 	 */
-	public static char[] getSignatureChar(ITypeBinding typeBinding) {
-		return SignatureUtils.getSignatureForTypeKey(typeBinding.getKey()).toCharArray();
+	public static String getSignature(ITypeBinding typeBinding) {
+		if (typeBinding.isArray()) {
+			return Signature.createArraySignature(getSignature(typeBinding.getComponentType()), 1);
+		}
+		if (typeBinding.isWildcardType()) {
+			return Signature.createTypeParameterSignature(typeBinding.getName(), typeBinding.getBound() != null ? new String[] { getSignature(typeBinding.getBound()) } : null);
+		}
+		ITypeBinding[] typeBounds = typeBinding.getTypeBounds();
+		if (typeBinding.isTypeVariable() || typeBinding.isWildcardType()) {
+			return Signature.C_TYPE_VARIABLE + typeBinding.getName() + Signature.C_NAME_END;
+		}
+		if (typeBinding.isIntersectionType()) {
+			return Signature.createIntersectionTypeSignature(Stream.of(typeBounds).map(SignatureUtils::getSignature).toArray(String[]::new));
+		}
+		if (typeBinding.isParameterizedType()) {
+			StringBuilder res = new StringBuilder(Signature.createTypeSignature(typeBinding.getErasure().getQualifiedName(), true));
+			res.deleteCharAt(res.length() - 1);
+			return res.toString()
+				+ Signature.C_GENERIC_START
+				+ Stream.of(typeBinding.getTypeArguments()).map(SignatureUtils::getSignature).collect(Collectors.joining())
+				+ Signature.C_GENERIC_END
+				+ Signature.C_NAME_END;
+		}
+		if (typeBinding.isGenericType()) {
+			StringBuilder res = new StringBuilder(Signature.createTypeSignature(typeBinding.getErasure().getQualifiedName(), true));
+			res.deleteCharAt(res.length() - 1);
+			return res.toString()
+				+ Signature.C_GENERIC_START
+				+ Stream.of(typeBinding.getTypeParameters()).map(SignatureUtils::getSignature).collect(Collectors.joining())
+				+ Signature.C_GENERIC_END
+				+ Signature.C_NAME_END;
+		}
+		return SignatureUtils.getSignatureForTypeKey(typeBinding.getKey());
 	}
 
 	/**

org.eclipse.jdt.core.javac/src/org/eclipse/jdt/internal/codeassist/DOMCompletionEngine.java

@@ -159,6 +159,7 @@
 import org.eclipse.jdt.core.search.SearchPattern;
 import org.eclipse.jdt.core.search.TypeNameMatch;
 import org.eclipse.jdt.core.search.TypeNameMatchRequestor;
+import org.eclipse.jdt.internal.SignatureUtils;
 import org.eclipse.jdt.internal.codeassist.impl.AssistOptions;
 import org.eclipse.jdt.internal.codeassist.impl.Keywords;
 import org.eclipse.jdt.internal.codeassist.impl.RestrictedIdentifiers;

org.eclipse.jdt.core.javac/src/org/eclipse/jdt/internal/codeassist/DOMCompletionUtil.java

@@ -31,6 +31,7 @@
 import org.eclipse.jdt.core.dom.FieldAccess;
 import org.eclipse.jdt.core.dom.ITypeBinding;
 import org.eclipse.jdt.core.dom.Modifier.ModifierKeyword;
+import org.eclipse.jdt.internal.SignatureUtils;
 import org.eclipse.jdt.core.dom.QualifiedName;
 import org.eclipse.jdt.core.dom.SuperMethodReference;
 import org.eclipse.jdt.core.dom.TypeMethodReference;

org.eclipse.jdt.core.javac/src/org/eclipse/jdt/internal/javac/dom/JavacMethodBinding.java

@@ -18,6 +18,7 @@
 import java.util.Objects;
 import java.util.Set;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 import org.eclipse.jdt.core.IMethod;
 import org.eclipse.jdt.core.IType;
@@ -36,6 +37,7 @@
 import org.eclipse.jdt.core.dom.SingleVariableDeclaration;
 import org.eclipse.jdt.core.dom.TypeParameter;
 import org.eclipse.jdt.core.dom.JavacBindingResolver.BindingKeyException;
+import org.eclipse.jdt.internal.SignatureUtils;
 import org.eclipse.jdt.internal.core.BinaryMethod;
 import org.eclipse.jdt.internal.core.JavaElement;
 import org.eclipse.jdt.internal.core.Member;
@@ -280,6 +282,10 @@ private IMethod getJavaElementForMethodDeclaration(IType currentType, MethodDecl
 			typeParamsList.add(typeParams.get(i).getName().toString());
 		}
 
+		IMethod result = currentType.getMethod(getName(), Stream.of(getParameterTypes()).map(SignatureUtils::getSignature).toArray(String[]::new));
+		if (result.exists()) {
+			return result;
+		}
 		List<SingleVariableDeclaration> p = methodDeclaration.parameters();
 		String[] params = p.stream() //
 				.map(param -> {
@@ -289,10 +295,11 @@ private IMethod getJavaElementForMethodDeclaration(IType currentType, MethodDecl
 					}
 					return sig;
 				}).toArray(String[]::new);
-		IMethod result = currentType.getMethod(getName(), params);
-		if (currentType.isBinary() || result.exists()) {
+		result = currentType.getMethod(getName(), params);
+		if (result.exists()) {
 			return result;
 		}
+
 		IMethod[] methods = null;
 		try {
 			methods = currentType.getMethods();

org.eclipse.jdt.core.javac/src/org/eclipse/jdt/internal/javac/dom/JavacTypeBinding.java

@@ -55,6 +55,7 @@
 import org.eclipse.jdt.core.dom.ITypeBinding;
 import org.eclipse.jdt.core.dom.IVariableBinding;
 import org.eclipse.jdt.core.dom.JavacBindingResolver;
+import org.eclipse.jdt.core.dom.JavacCompilationUnitResolver;
 import org.eclipse.jdt.core.dom.MethodDeclaration;
 import org.eclipse.jdt.core.dom.Modifier;
 import org.eclipse.jdt.core.dom.RecordDeclaration;
@@ -255,7 +256,7 @@ private IJavaElement computeJavaElement() {
 				}
 			}
 			ITypeRoot typeRoot = null;
-			if (jfo != null) {
+			if (jfo != null && !jfo.getName().endsWith(JavacCompilationUnitResolver.MOCK_NAME_FOR_CLASSES)) {
 				var jfoFile = new File(jfo.getName());
 				var jfoPath = new Path(jfo.getName());
 				Stream<IFile> fileStream = jfoFile.isFile()	?
@@ -577,7 +578,7 @@ static void getKey(StringBuilder builder, Type typeToBuild, String n, boolean is
 					} catch (IllegalArgumentException e) {
 						// probably: uri is not a valid path
 					}
-					if (fileName != null && !fileName.startsWith(classSymbol.getSimpleName().toString())) {
+					if (fileName != null && !fileName.startsWith(classSymbol.getSimpleName().toString()) && !fileName.endsWith(JavacCompilationUnitResolver.MOCK_NAME_FOR_CLASSES)) {
 						// There are multiple top-level types in this file,
 						// inject 'FileName~' before the type name to show that this type came from `FileName.java`
 						// (eg. Lorg/eclipse/jdt/FileName~MyTopLevelType;)