diff --git a/source/dub/commandline.d b/source/dub/commandline.d
index f2b9b19..e7304de 100644
--- a/source/dub/commandline.d
+++ b/source/dub/commandline.d
@@ -430,13 +430,13 @@
 		{
 			string msg = "Unknown build configuration: "~m_buildConfig;
 			enum distance = 3;
-			if (auto match = dub.configurations.getClosestMatch(m_buildConfig, distance))
-				msg ~= ". Did you mean '" ~ match ~ "'?";
+			auto match = dub.configurations.getClosestMatch(m_buildConfig, distance);
+			if (match !is null) msg ~= ". Did you mean '" ~ match ~ "'?";
 			enforce(0, msg);
 		}
 
 		if (m_buildType.length == 0) {
-			if (environment.get("DFLAGS")) m_buildType = "$DFLAGS";
+			if (environment.get("DFLAGS") !is null) m_buildType = "$DFLAGS";
 			else m_buildType = "debug";
 		}
 
@@ -1563,13 +1563,13 @@
 		assert(names.length == 1 || names.length == 2);
 		string sarg = names[0].length == 1 ? names[0] : null;
 		string larg = names[0].length > 1 ? names[0] : names.length > 1 ? names[1] : null;
-		if (sarg) {
+		if (sarg !is null) {
 			writeWS(shortArgColumn);
 			writef("-%s", sarg);
 			writeWS(longArgColumn - shortArgColumn - 2);
 		} else writeWS(longArgColumn);
 		size_t col = longArgColumn;
-		if (larg) {
+		if (larg !is null) {
 			if (arg.defaultValue.peek!bool) {
 				writef("--%s", larg);
 				col += larg.length + 2;
diff --git a/source/dub/dependencyresolver.d b/source/dub/dependencyresolver.d
index 36804a0..6807295 100644
--- a/source/dub/dependencyresolver.d
+++ b/source/dub/dependencyresolver.d
@@ -175,7 +175,7 @@
 			visited = null;
 			string error;
 			auto conflict_index = validateConfigs(root, error);
-			if (!first_error) first_error = error;
+			if (first_error !is null) first_error = error;
 
 			// print out current iteration state
 			logDebug("Interation (ci=%s) %s", conflict_index, {
diff --git a/source/dub/package_.d b/source/dub/package_.d
index 0f3d895..795c417 100644
--- a/source/dub/package_.d
+++ b/source/dub/package_.d
@@ -561,7 +561,8 @@
 		return null;
 	}
 
-	if (auto tag = exec("git", git_dir_param, "describe", "--long", "--tags")) {
+	auto tag = exec("git", git_dir_param, "describe", "--long", "--tags");
+	if (tag !is null) {
 		auto parts = tag.split("-");
 		auto commit = parts[$-1];
 		auto num = parts[$-2].to!int;
@@ -573,7 +574,8 @@
 		}
 	}
 
-	if (auto branch = exec("git", git_dir_param, "rev-parse", "--abbrev-ref", "HEAD")) {
+	auto branch = exec("git", git_dir_param, "rev-parse", "--abbrev-ref", "HEAD");
+	if (branch !is null) {
 		if (branch != "HEAD") return "~" ~ branch;
 	}
 
diff --git a/source/dub/project.d b/source/dub/project.d
index 0d824c1..8a3b7d9 100644
--- a/source/dub/project.d
+++ b/source/dub/project.d
@@ -825,7 +825,8 @@
 				return prj.path.toNativeString();
 	}
 
-	if (auto envvar = environment.get(name)) return envvar;
+	auto envvar = environment.get(name)
+	if (envvar !is null) return envvar;
 
 	throw new Exception("Invalid variable: "~name);
 }
diff --git a/source/dub/recipe/json.d b/source/dub/recipe/json.d
index ccf2a59..c7730c3 100644
--- a/source/dub/recipe/json.d
+++ b/source/dub/recipe/json.d
@@ -90,7 +90,7 @@
 		}
 		ret.subPackages = jsonSubPackages;
 	}
-	if (recipe.configurations) {
+	if (recipe.configurations.length) {
 		Json[] configs;
 		foreach(config; recipe.configurations)
 			configs ~= config.toJson();