diff --git a/src/config.h b/src/config.h
index e0ccf2a1..9b73c709 100644
--- a/src/config.h
+++ b/src/config.h
@@ -90,6 +90,11 @@ struct Config {
   // If true parameter declarations are included in code completion when calling
   // a function or method
   bool enableSnippetInsertion = true;
+
+  //// For debugging
+
+  // Dump AST after parsing if some pattern matches the source filename.
+  std::vector<std::string> dumpAST;
 };
 MAKE_REFLECT_STRUCT(Config,
                     compilationDatabaseDirectory,
@@ -125,7 +130,10 @@ MAKE_REFLECT_STRUCT(Config,
                     codeLensOnLocalVariables,
 
                     clientVersion,
-                    enableSnippetInsertion);
+                    enableSnippetInsertion,
+
+                    dumpAST
+                    );
 
 // Expected client version. We show an error if this doesn't match.
 constexpr const int kExpectedClientVersion = 3;
diff --git a/src/iindexer.cc b/src/iindexer.cc
index ba86ecd3..1753f23b 100644
--- a/src/iindexer.cc
+++ b/src/iindexer.cc
@@ -13,8 +13,14 @@ struct ClangIndexer : IIndexer {
       const std::vector<std::string>& args,
       const std::vector<FileContents>& file_contents,
       PerformanceImportFile* perf) override {
+    bool dump_ast = false;
+    for (const std::string& pattern : config->dumpAST)
+      if (file.find(pattern) != std::string::npos) {
+        dump_ast = true;
+        break;
+      }
     return Parse(config, file_consumer_shared, file, args, file_contents, perf,
-                 &index);
+                 &index, dump_ast);
   }
 
   // Note: constructing this acquires a global lock