Don't check import selectors for Java code

compiler/src/dotty/tools/dotc/typer/Checking.scala

@@ -1460,8 +1460,9 @@ trait Checking {
         report.error(ImportRenamedTwice(sel.imported), sel.imported.srcPos)
       seen += sel.name
 
-    for sel <- selectors do
-      if !sel.isWildcard then checkIdent(sel)
+    if !ctx.compilationUnit.isJava then
+      for sel <- selectors do
+        if !sel.isWildcard then checkIdent(sel)
   end checkImportSelectors
 }
 

tests/pos/i15608/bar/Test.scala

@@ -0,0 +1,6 @@
+package bar
+
+trait MDCAdapter
+
+object ScalaMDCAdapter extends MDCAdapter {
+}

tests/pos/i15608/foo/JavaMDCBinder.java

@@ -0,0 +1,20 @@
+package foo;
+
+import bar.MDCAdapter;
+import bar.ScalaMDCAdapter;
+import bar.ScalaMDCAdapter$;
+
+public class JavaMDCBinder {
+    public static final JavaMDCBinder SINGLETON = new JavaMDCBinder();
+
+    private JavaMDCBinder() {
+    }
+
+    public MDCAdapter getMDCA() {
+        return ScalaMDCAdapter$.MODULE$;
+    }
+
+    public String getMDCAdapterClassStr() {
+        return ScalaMDCAdapter.class.getName();
+    }
+}