From bb3e25b257d86de2970555ca49c0747e1e7cef44 Mon Sep 17 00:00:00 2001
From: Stephan Herrmann <stephan.herrmann@berlin.de>
Date: Wed, 19 Jun 2024 20:10:35 +0200
Subject: [PATCH] [23] ECJ rejects 'module' as top level package in an import
 statement

fixes https://github.com/eclipse-jdt/eclipse.jdt.core/issues/2607
---
 .../jdt/internal/compiler/parser/Scanner.java | 16 ++++++--
 .../regression/ModuleImportTests.java         | 38 ++++++++++++++++++-
 2 files changed, 49 insertions(+), 5 deletions(-)

diff --git a/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/parser/Scanner.java b/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/parser/Scanner.java
index b5487f0a926..2f9243ecbd8 100644
--- a/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/parser/Scanner.java
+++ b/org.eclipse.jdt.core.compiler.batch/src/org/eclipse/jdt/internal/compiler/parser/Scanner.java
@@ -2759,6 +2759,11 @@ protected boolean areRestrictedModuleKeywordsActive() {
 	return this.scanContext != null && this.scanContext != ScanContext.INACTIVE;
 }
 void updateScanContext(int token) {
+	if (this.scanContext == ScanContext.AFTER_IMPORT && !isInModuleDeclaration()) {
+		this.scanContext = ScanContext.INACTIVE; // end temporary use of scanContext to disambiguate module imports
+		return;
+	}
+
 	switch (token) {
 		case TerminalTokens.TokenNameSEMICOLON:	// next could be a KEYWORD
 		case TerminalTokens.TokenNameRBRACE:
@@ -3536,10 +3541,14 @@ else if ((data[index] == 'o')
 						&& (data[++index] == 'p')
 						&& (data[++index] == 'o')
 						&& (data[++index] == 'r')
-						&& (data[++index] == 't'))
+						&& (data[++index] == 't')) {
+						// initialize scanContext, because we need disambiguation when the next token is 'module':
+						if (this.scanContext == null || this.scanContext == ScanContext.INACTIVE)
+							this.scanContext = ScanContext.EXPECTING_IDENTIFIER;
 						return TokenNameimport;
-					else
+					} else {
 						return TokenNameIdentifier;
+					}
 				case 9 :
 					if ((data[++index] == 'n')
 						&& (data[++index] == 't')
@@ -3596,8 +3605,7 @@ else if ((data[index] == 'o')
 		case 'm': //module
 			switch (length) {
 				case 6 :
-					if ((areRestrictedModuleKeywordsActive()
-							|| this.lookBack[1] == TokenNameimport) // JEP 467: import module
+					if ((areRestrictedModuleKeywordsActive()) // JEP 467: import module
 						&& (data[++index] == 'o')
 						&& (data[++index] == 'd')
 						&& (data[++index] == 'u')
diff --git a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/ModuleImportTests.java b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/ModuleImportTests.java
index 800021dbade..b321dd02cf6 100644
--- a/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/ModuleImportTests.java
+++ b/org.eclipse.jdt.core.tests.compiler/src/org/eclipse/jdt/core/tests/compiler/regression/ModuleImportTests.java
@@ -47,7 +47,7 @@ public static Class<?> testClass() {
 	@Override
 	protected StringBuilder trimJavacLog(StringBuilder log) {
 		// suppress preview warnings from javac:
-		if (log.substring(0, 6).equals("Note: ")) {
+		if (log.length() > 6 && log.substring(0, 6).equals("Note: ")) {
 			StringBuilder filtered = new StringBuilder();
 			filtered.append(
 				log.toString().lines()
@@ -710,4 +710,40 @@ public class X {
 	        "",
 	        true);
 	}
+
+	public void test014_moduleAsPackageName_regular() {
+		List<String> files = new ArrayList<>();
+		writeFileCollecting(files, OUTPUT_DIR + File.separator + "module", "Z.java",
+				"""
+					package module;
+					public class Z {}
+					""");
+		writeFileCollecting(files, OUTPUT_DIR + File.separator + "test", "X.java",
+				"""
+					package test;
+					import module.Z;
+					public class X extends Z {}
+					""");
+		StringBuilder commandLine = new StringBuilder(" -23 --enable-preview");
+		runConformModuleTest(files, commandLine, "", "");
+	}
+
+
+	public void test014_moduleAsPackageName_moduleInfo() {
+		List<String> files = new ArrayList<>();
+		writeFileCollecting(files, OUTPUT_DIR + File.separator + "module", "Z.java",
+				"""
+					package module;
+					public class Z {}
+					""");
+		writeFileCollecting(files, OUTPUT_DIR, "module-info.java",
+				"""
+					import module.Z;
+					module one {
+						uses Z;
+					}
+					""");
+		StringBuilder commandLine = new StringBuilder(" -23 --enable-preview");
+		runConformModuleTest(files, commandLine, "", "");
+	}
 }