8341070: javac fails with an exception when compiling import module under source level 8

Reviewed-by: asotona

Author: lahodaj

src/jdk.compiler/share/classes/com/sun/tools/javac/code/Symtab.java

@@ -420,14 +420,30 @@ protected Symtab(Context context) throws CompletionFailure {
                                             missingInfoHandler,
                                             target.runtimeUseNestAccess());
 
+        noModule = new ModuleSymbol(names.empty, null) {
+            @Override public boolean isNoModule() {
+                return true;
+            }
+        };
+        addRootPackageFor(noModule);
+
+        Source source = Source.instance(context);
+        if (Feature.MODULES.allowedInSource(source)) {
+            java_base = enterModule(names.java_base);
+            //avoid completing java.base during the Symtab initialization
+            java_base.completer = Completer.NULL_COMPLETER;
+            java_base.visiblePackages = Collections.emptyMap();
+        } else {
+            java_base = noModule;
+        }
+
         // create the basic builtin symbols
         unnamedModule = new ModuleSymbol(names.empty, null) {
                 {
                     directives = List.nil();
                     exports = List.nil();
                     provides = List.nil();
                     uses = List.nil();
-                    ModuleSymbol java_base = enterModule(names.java_base);
                     com.sun.tools.javac.code.Directive.RequiresDirective d =
                             new com.sun.tools.javac.code.Directive.RequiresDirective(java_base,
                                     EnumSet.of(com.sun.tools.javac.code.Directive.RequiresFlag.MANDATED));
@@ -447,7 +463,6 @@ public String toString() {
                     exports = List.nil();
                     provides = List.nil();
                     uses = List.nil();
-                    ModuleSymbol java_base = enterModule(names.java_base);
                     com.sun.tools.javac.code.Directive.RequiresDirective d =
                             new com.sun.tools.javac.code.Directive.RequiresDirective(java_base,
                                     EnumSet.of(com.sun.tools.javac.code.Directive.RequiresFlag.MANDATED));
@@ -456,13 +471,6 @@ public String toString() {
             };
         addRootPackageFor(errModule);
 
-        noModule = new ModuleSymbol(names.empty, null) {
-            @Override public boolean isNoModule() {
-                return true;
-            }
-        };
-        addRootPackageFor(noModule);
-
         noSymbol = new TypeSymbol(NIL, 0, names.empty, Type.noType, rootPackage) {
             @Override @DefinedBy(Api.LANGUAGE_MODEL)
             public <R, P> R accept(ElementVisitor<R, P> v, P p) {
@@ -526,16 +534,6 @@ public <R, P> R accept(ElementVisitor<R, P> v, P p) {
         // Enter symbol for the errSymbol
         scope.enter(errSymbol);
 
-        Source source = Source.instance(context);
-        if (Feature.MODULES.allowedInSource(source)) {
-            java_base = enterModule(names.java_base);
-            //avoid completing java.base during the Symtab initialization
-            java_base.completer = Completer.NULL_COMPLETER;
-            java_base.visiblePackages = Collections.emptyMap();
-        } else {
-            java_base = noModule;
-        }
-
         // Get the initial completer for ModuleSymbols from Modules
         moduleCompleter = Modules.instance(context).getCompleter();
 

test/langtools/tools/javac/ImportModule.java

@@ -797,4 +797,50 @@ public class C {}
 
         }
     }
+
+    @Test
+    public void testImportModuleNoModules(Path base) throws Exception {
+        Path current = base.resolve(".");
+        Path src = current.resolve("src");
+        Path classes = current.resolve("classes");
+        tb.writeJavaFiles(src,
+                          """
+                          package test;
+                          import module java.base;
+                          public class Test {
+                              List<String> l;
+                          }
+                          """);
+
+        Files.createDirectories(classes);
+
+        List<String> actualErrors = new JavacTask(tb)
+            .options("--release", "8",
+                     "-XDshould-stop.at=FLOW",
+                     "-XDdev",
+                     "-XDrawDiagnostics")
+            .outdir(classes)
+            .files(tb.findJavaFiles(src))
+            .run(Task.Expect.FAIL)
+            .writeAll()
+            .getOutputLines(Task.OutputKind.DIRECT);
+
+        List<String> expectedErrors = List.of(
+                "- compiler.warn.option.obsolete.source: 8",
+                "- compiler.warn.option.obsolete.target: 8",
+                "- compiler.warn.option.obsolete.suppression",
+                "Test.java:2:8: compiler.err.preview.feature.disabled.plural: (compiler.misc.feature.module.imports)",
+                "Test.java:2:1: compiler.err.import.module.not.found: java.base",
+                "Test.java:4:5: compiler.err.cant.resolve.location: kindname.class, List, , , (compiler.misc.location: kindname.class, test.Test, null)",
+                "3 errors",
+                "3 warnings"
+        );
+
+        if (!Objects.equals(expectedErrors, actualErrors)) {
+            throw new AssertionError("Incorrect Output, expected: " + expectedErrors +
+                                      ", actual: " + out);
+
+        }
+    }
+
 }