Sanitize base namespace for generated code

src/Microsoft.AspNetCore.Blazor.Razor.Extensions/ComponentDocumentClassifierPass.cs

@@ -25,6 +25,8 @@ public class ComponentDocumentClassifierPass : DocumentClassifierPassBase, IRazo
 
         private static readonly char[] PathSeparators = new char[] { '/', '\\' };
 
+        private static readonly char[] NamespaceSeparators = new char[] { '.' };
+
         /// <summary>
         /// The base namespace.
         /// </summary>
@@ -141,9 +143,20 @@ private bool TryComputeNamespaceAndClass(string filePath, string relativePath, o
             }
 
             var builder = new StringBuilder();
-            builder.Append(baseNamespace); // Don't sanitize, we expect it to contain dots.
 
-            var segments = relativePath.Split(PathSeparators, StringSplitOptions.RemoveEmptyEntries);
+            // Sanitize the base namespace, but leave the dots.
+            var segments = baseNamespace.Split(NamespaceSeparators, StringSplitOptions.RemoveEmptyEntries);
+            builder.Append(CSharpIdentifier.SanitizeClassName(segments[0]));
+            if (segments.Length > 1)
+            {
+                for (var i = 1; i < segments.Length; i++)
+                {
+                    builder.Append('.');
+                    builder.Append(CSharpIdentifier.SanitizeClassName(segments[i]));
+                }
+            }
+
+            segments = relativePath.Split(PathSeparators, StringSplitOptions.RemoveEmptyEntries);
 
             // Skip the last segment because it's the FileName.
             for (var i = 0; i < segments.Length - 1; i++)