diff --git a/include/bolt/Diagnostics.hpp b/include/bolt/Diagnostics.hpp
index ddefc9d48..b52420d53 100644
--- a/include/bolt/Diagnostics.hpp
+++ b/include/bolt/Diagnostics.hpp
@@ -1,8 +1,8 @@
 
 #pragma once
 
-#include <cwchar>
 #include <vector>
+#include <filesystem>
 
 #include "bolt/ByteString.hpp"
 #include "bolt/String.hpp"
@@ -22,6 +22,7 @@ enum class DiagnosticKind : unsigned char {
   UnexpectedString,
   UnexpectedToken,
   TypeMismatchError,
+  OpenFileFailedDiagnostic,
 };
 
 class Diagnostic {
@@ -119,4 +120,25 @@ public:
 
 };
 
+class OpenFileFailedDiagnostic : public Diagnostic {
+public:
+
+  std::filesystem::path Filename;
+  std::error_code Code;
+
+  inline OpenFileFailedDiagnostic(
+    std::filesystem::path Filename,
+    std::error_code Code
+  ): Diagnostic(DiagnosticKind::OpenFileFailedDiagnostic), Filename(Filename), Code(Code) {}
+
+  inline Node* getNode() const override {
+    return nullptr;
+  }
+
+  unsigned getCode() const override {
+    return 101;
+  }
+
+};
+
 }
diff --git a/src/ConsolePrinter.cc b/src/ConsolePrinter.cc
index c59a56d3d..d6f50b004 100644
--- a/src/ConsolePrinter.cc
+++ b/src/ConsolePrinter.cc
@@ -1,6 +1,7 @@
 
 // FIXME writeExcerpt does not work well with the last line in a file
 
+#include <cstring>
 #include <functional>
 #include <cmath>
 
@@ -608,6 +609,16 @@ void ConsolePrinter::writeDiagnostic(const Diagnostic& D) {
       return;
     }
 
+    case DiagnosticKind::OpenFileFailedDiagnostic:
+    {
+        auto E = static_cast<const OpenFileFailedDiagnostic&>(D);
+        write("failed to open file ");
+        write(E.Filename.c_str());
+        write(": ");
+        write(strerror(E.Code.value()));
+        return;
+    }
+
     case DiagnosticKind::TypeMismatchError:
     {
       auto& E = static_cast<const TypeMismatchError&>(D);