From 9a685523f9e8bc5888adb60df3871d2b43c0b81f Mon Sep 17 00:00:00 2001
From: Geod24 <pro.mathias.lang@gmail.com>
Date: Mon, 31 Aug 2020 11:17:55 +0900
Subject: [PATCH] Add support for DMD 2.094 -preview=in switch

This will allow users to use -preview=in as soon as it's released.
---
 source/vibe/core/file.d        | 15 ++++++++++++++-
 source/vibe/core/task.d        | 11 +++++++++--
 source/vibe/internal/hashmap.d |  7 ++++---
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/source/vibe/core/file.d b/source/vibe/core/file.d
index 697f439..bce1f93 100644
--- a/source/vibe/core/file.d
+++ b/source/vibe/core/file.d
@@ -717,7 +717,20 @@ struct DirectoryWatcher { // TODO: avoid all those heap allocations!
 		LocalManualEvent changeEvent;
 		shared(NativeEventDriver) driver;
 
-		void onChange(WatcherID, in ref FileChange change)
+		// Support for `-preview=in`
+		static if (!is(typeof(mixin(q{(in ref int a) => a}))))
+		{
+			void onChange(WatcherID id, in FileChange change) nothrow {
+				this.onChangeImpl(id, change);
+			}
+		} else {
+			mixin(q{
+			void onChange(WatcherID id, in ref FileChange change) nothrow {
+				this.onChangeImpl(id, change);
+			}});
+		}
+
+		void onChangeImpl(WatcherID, const scope ref FileChange change)
 		nothrow {
 			DirectoryChangeType ct;
 			final switch (change.kind) {
diff --git a/source/vibe/core/task.d b/source/vibe/core/task.d
index ef113e7..9dfbfbc 100644
--- a/source/vibe/core/task.d
+++ b/source/vibe/core/task.d
@@ -127,8 +127,15 @@ struct Task {
 		return app.data;
 	}
 
-	bool opEquals(in ref Task other) const @safe nothrow { return m_fiber is other.m_fiber && m_taskCounter == other.m_taskCounter; }
-	bool opEquals(in Task other) const @safe nothrow { return m_fiber is other.m_fiber && m_taskCounter == other.m_taskCounter; }
+	// Remove me when `-preview=in` becomes the default
+	static if (is(typeof(mixin(q{(in ref int a) => a}))))
+		mixin(q{
+			bool opEquals(in ref Task other) const @safe nothrow {
+				return m_fiber is other.m_fiber && m_taskCounter == other.m_taskCounter;
+			}});
+	bool opEquals(in Task other) const @safe nothrow {
+		return m_fiber is other.m_fiber && m_taskCounter == other.m_taskCounter;
+	}
 }
 
 
diff --git a/source/vibe/internal/hashmap.d b/source/vibe/internal/hashmap.d
index d803eb6..b0b427f 100644
--- a/source/vibe/internal/hashmap.d
+++ b/source/vibe/internal/hashmap.d
@@ -20,7 +20,8 @@ struct DefaultHashMapTraits(Key) {
 		static if (is(Key == class)) return a is b;
 		else return a == b;
 	}
-	static size_t hashOf(in ref Key k)
+
+	static size_t hashOf(const scope ref Key k)
 	{
 		static if (is(Key == class) && &Key.toHash == &Object.toHash)
 			return cast(size_t)cast(void*)k;
@@ -31,11 +32,11 @@ struct DefaultHashMapTraits(Key) {
 		else {
 			// evil casts to be able to get the most basic operations of
 			// HashMap nothrow and @nogc
-			static size_t hashWrapper(in ref Key k) {
+			static size_t hashWrapper(scope const ref Key k) {
 				static typeinfo = typeid(Key);
 				return typeinfo.getHash(&k);
 			}
-			static @nogc nothrow size_t properlyTypedWrapper(in ref Key k) { return 0; }
+			static @nogc nothrow size_t properlyTypedWrapper(scope const ref Key k) { return 0; }
 			return () @trusted { return (cast(typeof(&properlyTypedWrapper))&hashWrapper)(k); } ();
 		}
 	}