diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2ce0082..df51d0d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,6 +16,9 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_C_STANDARD            11)
 set(CMAKE_C_STANDARD_REQUIRED   ON)
 
+set(CMAKE_C_VISIBILITY_PRESET hidden)
+set(CMAKE_CXX_VISIBILITY_PRESET hidden)
+
 set(CMAKE_EXPORT_COMPILE_COMMANDS ON)   # For JetBrains IDE
 
 
@@ -49,11 +52,12 @@ if (MSVC)
     # MSVC:
     add_definitions(-DWIN32_LEAN_AND_MEAN -D_WIN32_WINNT=0x0A00 -DNOMINMAX)
     add_compile_options(
-        /W4         # I think this means 'turn on lots of warnings'
-        /wd4068     # ignore unknown pragma
-        /wd4100     # ignore unused fn parameters
-        /wd4244     # ignore implicit sign conversion
-        /wd4267     # ignore implicit integer truncation
+        "/wd4068;/wd4100;/wd4244;/wd4267"
+       # /W4         # I think this means 'turn on lots of warnings'
+       # /wd4068     # ignore unknown pragma
+       # /wd4100     # ignore unused fn parameters
+       # /wd4244     # ignore implicit sign conversion
+       # /wd4267     # ignore implicit integer truncation
     )
 else()
     # Clang & GCC:
@@ -76,7 +80,8 @@ else()
         add_compile_options(
             -Wno-gnu-zero-variadic-macro-arguments
             -Wno-gnu-conditional-omitted-operand    # Allow `x ?: y`
-            -Wno-gnu-statement-expression-from-macro-expansion  # Allow `({...})`
+            -Wno-gnu-statement-expression           # Allow `({...})`
+            -Wno-gnu-statement-expression-from-macro-expansion
         )
     endif()
 endif()
diff --git a/include/Awaitable.hh b/include/Awaitable.hh
index 135f530..1bdbc1f 100644
--- a/include/Awaitable.hh
+++ b/include/Awaitable.hh
@@ -19,6 +19,8 @@
 #pragma once
 #include "Result.hh"
 
+#include <functional>
+
 namespace crouton {
 
     /** Pure-virtual interface declaring the coroutine methods needed to support `co_await`
diff --git a/include/Base.hh b/include/Base.hh
index 5f5eee9..fb58fce 100644
--- a/include/Base.hh
+++ b/include/Base.hh
@@ -42,6 +42,23 @@
 #endif
 
 
+#ifndef __has_attribute
+#define __has_attribute(x) 0
+#endif
+
+#if __has_attribute(__unused__)
+#define __unused    __attribute__((__unused__))
+#else
+#define __unused
+#endif
+
+#if __has_attribute(__pure__)
+#define pure        __attribute__((__pure__))
+#else
+#define pure
+#endif
+
+
 // Synonyms for coroutine primitives. Optional, but they're more visible in the code.
 #define AWAIT  co_await
 #define YIELD  co_yield
diff --git a/include/Error.hh b/include/Error.hh
index 1b9cd3b..fb52dff 100644
--- a/include/Error.hh
+++ b/include/Error.hh
@@ -21,7 +21,7 @@
 
 #include <array>
 #include <concepts>
-#include <exception>
+#include <stdexcept>
 #include <type_traits>
 #include <typeinfo>
 
@@ -51,7 +51,7 @@ namespace crouton {
     template <typename T>
     concept ErrorDomain = requires {
         std::is_enum_v<T>;
-        std::same_as<std::underlying_type_t<T>, errorcode_t>;
+        requires std::same_as<std::underlying_type_t<T>, errorcode_t>;
         {ErrorDomainInfo<T>::name} -> std::convertible_to<string_view>;
         {ErrorDomainInfo<T>::description} -> std::convertible_to<ErrorDescriptionFunc>;
     };
diff --git a/include/EventLoop.hh b/include/EventLoop.hh
index dacdd17..f337f30 100644
--- a/include/EventLoop.hh
+++ b/include/EventLoop.hh
@@ -20,6 +20,7 @@
 #include "Future.hh"
 
 #include <functional>
+#include <optional>
 
 struct uv_timer_s;
 
diff --git a/include/Future.hh b/include/Future.hh
index 54e3b7f..6e783ff 100644
--- a/include/Future.hh
+++ b/include/Future.hh
@@ -61,7 +61,7 @@ namespace crouton {
     template <typename T>
     class Future : public Coroutine<FutureImpl<T>>, public ISelectable {
     public:
-        using nonvoidT = std::conditional<std::is_void_v<T>, std::byte, T>::type;
+        using nonvoidT = typename std::conditional<std::is_void_v<T>, std::byte, T>::type;
 
         /// Creates a Future from a FutureProvider.
         explicit Future(FutureProvider<T> state)        :_state(std::move(state)) {assert(_state);}
@@ -260,7 +260,7 @@ namespace crouton {
     public:
         using super = CoroutineImpl<FutureImpl<T>, true>;
         using handle_type = typename super::handle_type;
-        using nonvoidT = std::conditional<std::is_void_v<T>, std::byte, T>::type;
+        using nonvoidT = typename std::conditional<std::is_void_v<T>, std::byte, T>::type;
 
         FutureImpl() = default;
 
diff --git a/include/LinkedList.hh b/include/LinkedList.hh
index ca7b268..f33b0ab 100644
--- a/include/LinkedList.hh
+++ b/include/LinkedList.hh
@@ -111,6 +111,8 @@ namespace crouton::util {
     protected:
         Link* _begin()                  {return _head._next;}
         Link* _end()                    {return &_head;}
+        Link const* _begin() const      {return _head._next;}
+        Link const* _end() const        {return &_head;}
 
         template <class LINK>
         static LINK& downcast(Link& link)   {return static_cast<LINK&>(link);}
diff --git a/include/PubSub.hh b/include/PubSub.hh
index 3528d55..d35be65 100644
--- a/include/PubSub.hh
+++ b/include/PubSub.hh
@@ -12,6 +12,10 @@
 #include "Select.hh"
 #include "Task.hh"
 
+#include <functional>
+#include <optional>
+#include <vector>
+
 namespace crouton::ps {
 
     /** Type-erasing wrapper around any Series implementation. */
diff --git a/include/Queue.hh b/include/Queue.hh
index 90f13c9..9590569 100644
--- a/include/Queue.hh
+++ b/include/Queue.hh
@@ -87,8 +87,8 @@ namespace crouton {
         size_t size() const                         {return _queue.size();}
         Error error() const                         {return empty() ? _closeError : noerror;}
 
-        using iterator = std::deque<T>::iterator;
-        using const_iterator = std::deque<T>::const_iterator;
+        using iterator = typename std::deque<T>::iterator;
+        using const_iterator = typename std::deque<T>::const_iterator;
 
         iterator begin()                            {return _queue.begin();}
         iterator end()                              {return _queue.end();}
@@ -120,7 +120,7 @@ namespace crouton {
         }
 
         /// Adds an item at the position of the iterator, i.e. before whatever's at the iterator.
-        virtual bool pushBefore(std::deque<T>::iterator i, T item) {
+        virtual bool pushBefore(typename std::deque<T>::iterator i, T item) {
             if (_state != Open)
                 return false;
             _queue.emplace(i, std::move(item));
@@ -245,7 +245,7 @@ namespace crouton {
                     this->closeWhenEmpty();
                     break;
                 }
-                if (!(YIELD 0))
+                if (bool ok = YIELD 0; !ok)
                     break;
             }
         }
@@ -266,7 +266,7 @@ namespace crouton {
             return !full() && super::push(std::move(t));
         }
 
-        [[nodiscard]] bool pushBefore(std::deque<T>::iterator i, T item) override {
+        [[nodiscard]] bool pushBefore(typename std::deque<T>::iterator i, T item) override {
             return !full() && super::pushBefore(i, std::move(item));
         }
 
diff --git a/include/Result.hh b/include/Result.hh
index c26d994..048a8a0 100644
--- a/include/Result.hh
+++ b/include/Result.hh
@@ -133,6 +133,7 @@ namespace crouton {
 
 
 
+#if 0
     /// Syntactic sugar to handle a `Result<T>`, similar to Swift's `try`.
     /// - If R has a value, evaluates to its value.
     /// - If R has an error, `co_return`s the error from the current coroutine.
@@ -148,4 +149,5 @@ namespace crouton {
     /// - If the future returns a value, evaluates to that value.
     /// - If the future returns an error, `co_return`s the error.
     #define TRY_AWAIT(F)    UNWRAP(AWAIT NoThrow(F))
+#endif
 }
diff --git a/src/io/FileStream.cc b/src/io/FileStream.cc
index 0f1da1d..b4f0c0c 100644
--- a/src/io/FileStream.cc
+++ b/src/io/FileStream.cc
@@ -108,9 +108,10 @@ namespace crouton::io {
             _readBuf = make_unique<Buffer>();
         assert(_readBuf->empty());
         MutableBytes buf(_readBuf->data, Buffer::kCapacity);
-        size_t n = TRY_AWAIT(_preadv(&buf, 1, -1));
-
-        _readBuf->size = uint32_t(n);
+        Result<size_t> n = AWAIT _preadv(&buf, 1, -1);
+        if (auto err = n.error())
+            RETURN err;
+        _readBuf->size = uint32_t(n.value());
         _readBuf->used = 0;
         RETURN _readBuf->bytes();
     }
diff --git a/src/io/blip/BLIPConnection.hh b/src/io/blip/BLIPConnection.hh
index 055e8c9..5191f66 100644
--- a/src/io/blip/BLIPConnection.hh
+++ b/src/io/blip/BLIPConnection.hh
@@ -23,6 +23,10 @@
 #include "Message.hh"
 #include "Task.hh"
 
+#include <functional>
+#include <optional>
+#include <unordered_map>  
+
 namespace crouton::io::blip {
     class MessageBuilder;
 
diff --git a/src/io/blip/BLIPIO.hh b/src/io/blip/BLIPIO.hh
index 4ecd920..a2d53b6 100644
--- a/src/io/blip/BLIPIO.hh
+++ b/src/io/blip/BLIPIO.hh
@@ -19,7 +19,9 @@
 #include "Message.hh"
 #include "MessageOut.hh"
 #include "Queue.hh"
+
 #include <algorithm>
+#include <unordered_map>
 #include <vector>
 
 namespace crouton::io::blip {
diff --git a/src/io/blip/Message.cc b/src/io/blip/Message.cc
index 10dfaad..1391e74 100644
--- a/src/io/blip/Message.cc
+++ b/src/io/blip/Message.cc
@@ -214,11 +214,11 @@ namespace crouton::io::blip {
         _unackedBytes += frameSize;
         if (_unackedBytes >= kIncomingAckThreshold) {
             // Send an ACK after enough data has been received of this message:
-            MessageType msgType = isResponse() ? kAckResponseType : kAckRequestType;
+            auto msgType = FrameFlags(isResponse() ? kAckResponseType : kAckRequestType);
             char buf[10];
             string payload(buf, putUVarint(_rawBytesReceived, buf));
             _connection->send(make_shared<MessageOut>(_connection,
-                                                      (FrameFlags)(msgType|kUrgent|kNoReply),
+                                                      FrameFlags(msgType|kUrgent|kNoReply),
                                                       payload, _number));
             _unackedBytes = 0;
         }
diff --git a/src/io/blip/MessageBuilder.cc b/src/io/blip/MessageBuilder.cc
index aba0c65..f557c88 100644
--- a/src/io/blip/MessageBuilder.cc
+++ b/src/io/blip/MessageBuilder.cc
@@ -57,7 +57,7 @@ namespace crouton::io::blip {
 
 
     FrameFlags MessageBuilder::flags() const {
-        int flags = type & kTypeMask;
+        int flags = FrameFlags(type) & kTypeMask;
         if (urgent) flags |= kUrgent;
         if (compressed) flags |= kCompressed;
         if (noreply) flags |= kNoReply;
diff --git a/src/io/blip/MessageOut.cc b/src/io/blip/MessageOut.cc
index d1ddf7a..ac44724 100644
--- a/src/io/blip/MessageOut.cc
+++ b/src/io/blip/MessageOut.cc
@@ -99,7 +99,7 @@ namespace crouton::io::blip {
         // Note: The MessageIn's flags will be updated when the 1st frame of the response arrives;
         // the type might become kErrorType, and kUrgent or kCompressed might be set.
         return new MessageIn(_connection,
-                             (FrameFlags)kResponseType,
+                             FrameFlags(kResponseType),
                              _number,
                              _uncompressedBytesSent,
                              std::move(_onResponse));
diff --git a/src/support/StringUtils.hh b/src/support/StringUtils.hh
index 85fd6e2..b960e2f 100644
--- a/src/support/StringUtils.hh
+++ b/src/support/StringUtils.hh
@@ -18,6 +18,8 @@
 
 #pragma once
 #include "Base.hh"
+
+#include <cstring>
 #include <cassert>
 
 namespace crouton {
diff --git a/tests/test_generator.cc b/tests/test_generator.cc
index 1812a49..311280b 100644
--- a/tests/test_generator.cc
+++ b/tests/test_generator.cc
@@ -182,7 +182,7 @@ TEST_CASE("Select Future and Generator", "[generator]") {
         int64_t expectedCount = 1;
         bool done = false;
         while (!done) {
-            switch (int which = AWAIT select) {
+            switch (AWAIT select) {
                 case 0: {
                     Result<int64_t> r = AWAIT count;
                     cerr << r << ", ";