[fixes #1554] javac9 now caches type lookups based on ‘position’ which is slapped together by a tuple based on the position (as gleaned from the JCTree object) and the source file (as gleaned from.. Log. *facepalm*). We didn’t update log when resolving for i.e. ‘val’, so the caches get all jumbled up. Fixed by setting the Log’s ‘useSource’ method.

src/core/lombok/javac/JavacResolution.java

@@ -31,6 +31,7 @@ import java.util.ArrayDeque;
 import java.util.Map;
 
 import javax.lang.model.type.TypeKind;
+import javax.tools.JavaFileObject;
 
 import lombok.Lombok;
 import lombok.core.debug.AssertionLogger;
@@ -59,6 +60,7 @@ import com.sun.tools.javac.tree.JCTree.JCVariableDecl;
 import com.sun.tools.javac.util.Context;
 import com.sun.tools.javac.util.List;
 import com.sun.tools.javac.util.ListBuffer;
+import com.sun.tools.javac.util.Log;
 
 public class JavacResolution {
 	private final Attr attr;
@@ -142,9 +144,14 @@ public class JavacResolution {
 			
 			TreeMirrorMaker mirrorMaker = new TreeMirrorMaker(node.getTreeMaker(), node.getContext());
 			JCTree copy = mirrorMaker.copy(finder.copyAt());
-			
-			memberEnterAndAttribute(copy, finder.get(), node.getContext());
-			return mirrorMaker.getOriginalToCopyMap();
+			Log log = Log.instance(node.getContext());
+			JavaFileObject oldFileObject = log.useSource(((JCCompilationUnit) node.top().get()).getSourceFile());
+			try {
+				memberEnterAndAttribute(copy, finder.get(), node.getContext());
+				return mirrorMaker.getOriginalToCopyMap();
+			} finally {
+				log.useSource(oldFileObject);
+			}
 		} finally {
 			messageSuppressor.enableLoggers();
 		}

src/core/lombok/javac/handlers/HandleVal.java

@@ -62,21 +62,21 @@ public class HandleVal extends JavacASTAdapter {
 		JCTree typeTree = local.vartype;
 		if (typeTree == null) return;
 		String typeTreeToString = typeTree.toString();
-
+		
 		if (!(eq(typeTreeToString, "val") || eq(typeTreeToString, "var"))) return;
 		boolean isVal = typeMatches(val.class, localNode, typeTree);
 		boolean isVar = typeMatches(var.class, localNode, typeTree);
 		if (!(isVal || isVar)) return;
-
+		
 		if (isVal) handleFlagUsage(localNode, ConfigurationKeys.VAL_FLAG_USAGE, "val");
 		if (isVar) handleFlagUsage(localNode, ConfigurationKeys.VAR_FLAG_USAGE, "var");
-
+		
 		JCTree parentRaw = localNode.directUp().get();
 		if (isVal && parentRaw instanceof JCForLoop) {
 			localNode.addError("'val' is not allowed in old-style for loops");
 			return;
 		}
-
+		
 		JCExpression rhsOfEnhancedForLoop = null;
 		if (local.init == null) {
 			if (parentRaw instanceof JCEnhancedForLoop) {
@@ -84,26 +84,25 @@ public class HandleVal extends JavacASTAdapter {
 				if (efl.var == local) rhsOfEnhancedForLoop = efl.expr;
 			}
 		}
-
+		
 		final String annotation = typeTreeToString;
 		if (rhsOfEnhancedForLoop == null && local.init == null) {
 			localNode.addError("'" + annotation + "' on a local variable requires an initializer expression");
 			return;
-
 		}
-
+		
 		if (local.init instanceof JCNewArray && ((JCNewArray)local.init).elemtype == null) {
 			localNode.addError("'" + annotation + "' is not compatible with array initializer expressions. Use the full form (new int[] { ... } instead of just { ... })");
 			return;
 		}
-
+		
 		if (localNode.shouldDeleteLombokAnnotations()) {
 			JavacHandlerUtil.deleteImportFromCompilationUnit(localNode, val.class.getName());
 			JavacHandlerUtil.deleteImportFromCompilationUnit(localNode, var.class.getName());
 		}
-
+		
 		if (isVal) local.mods.flags |= Flags.FINAL;
-
+		
 		if (!localNode.shouldDeleteLombokAnnotations()) {
 			JCAnnotation valAnnotation = recursiveSetGeneratedBy(localNode.getTreeMaker().Annotation(local.vartype, List.<JCExpression>nil()), typeTree, localNode.getContext());
 			local.mods.annotations = local.mods.annotations == null ? List.of(valAnnotation) : local.mods.annotations.append(valAnnotation);
@@ -126,7 +125,7 @@ public class HandleVal extends JavacASTAdapter {
 					try {
 						type = ((JCExpression) resolver.resolveMethodMember(localNode).get(local.init)).type;
 					} catch (RuntimeException e) {
-						System.err.println("Exception while resolving: " + localNode);
+						System.err.println("Exception while resolving: " + localNode + "(" + localNode.getFileName() + ")");
 						throw e;
 					}
 				} else {
@@ -137,7 +136,7 @@ public class HandleVal extends JavacASTAdapter {
 							local.type = Symtab.instance(localNode.getContext()).unknownType;
 							type = ((JCExpression) resolver.resolveMethodMember(localNode).get(local.init)).type;
 						} catch (RuntimeException e) {
-							System.err.println("Exception while resolving: " + localNode);
+							System.err.println("Exception while resolving: " + localNode + "(" + localNode.getFileName() + ")");
 							throw e;
 						}
 					}