diff --git a/source/dub/dependency.d b/source/dub/dependency.d
index 301e339..e894e4e 100644
--- a/source/dub/dependency.d
+++ b/source/dub/dependency.d
@@ -316,7 +316,7 @@
 		These methods are suitable for equality comparisons, as well as for
 		using `Dependency` as a key in hash or tree maps.
 	*/
-	bool opEquals(const Dependency o)
+	bool opEquals(scope const Dependency o)
 	const {
 		// TODO(mdondorff): Check if not comparing the path is correct for all clients.
 		return this.m_range == o.m_range
@@ -324,7 +324,7 @@
 	}
 
 	/// ditto
-	int opCmp(const Dependency o)
+	int opCmp(scope const Dependency o)
 	const {
 		if (auto result = this.m_range.opCmp(o.m_range))
 			return result;
@@ -683,7 +683,6 @@
 	Semantic Versioning Specification v2.0.0 at http://semver.org/).
 */
 struct Version {
-@safe:
 	private {
 		static immutable MAX_VERS = "99999.0.0";
 		static immutable UNKNOWN_VERS = "unknown";
@@ -699,7 +698,7 @@
 
 	/** Constructs a new `Version` from its string representation.
 	*/
-	this(string vers)
+	this(string vers) @safe pure
 	{
 		enforce(vers.length > 1, "Version strings must not be empty.");
 		if (vers[0] != branchPrefix && !vers.isGitHash && vers.ptr !is UNKNOWN_VERS.ptr)
@@ -712,35 +711,52 @@
 		This method is equivalent to calling the constructor and is used as an
 		endpoint for the serialization framework.
 	*/
-	static Version fromString(string vers) { return Version(vers); }
+	static Version fromString(string vers) @safe pure { return Version(vers); }
 
-	bool opEquals(const Version oth) const { return opCmp(oth) == 0; }
+	bool opEquals(scope const Version oth) const scope @safe pure
+	{
+		return opCmp(oth) == 0;
+	}
 
 	/// Tests if this represents a hash instead of a version.
-	@property bool isSCM() const { return m_version.isGitHash; }
+	@property bool isSCM() const scope @safe pure nothrow @nogc
+	{
+		return m_version.isGitHash;
+	}
 
 	/// Tests if this represents a branch instead of a version.
-	@property bool isBranch() const { return m_version.length > 0 && m_version[0] == branchPrefix; }
+	@property bool isBranch() const scope @safe pure nothrow @nogc
+	{
+		return m_version.length > 0 && m_version[0] == branchPrefix;
+	}
 
 	/// Tests if this represents the master branch "~master".
-	@property bool isMaster() const { return m_version == masterString; }
+	@property bool isMaster() const scope @safe pure nothrow @nogc
+	{
+		return m_version == masterString;
+	}
 
 	/** Tests if this represents a pre-release version.
 
 		Note that branches are always considered pre-release versions.
 	*/
-	@property bool isPreRelease() const {
+	@property bool isPreRelease() const scope @safe pure nothrow @nogc
+	{
 		if (isBranch || isSCM) return true;
 		return isPreReleaseVersion(m_version);
 	}
 
 	/// Tests if this represents the special unknown version constant.
-	@property bool isUnknown() const { return m_version == UNKNOWN_VERS; }
+	@property bool isUnknown() const scope @safe pure nothrow @nogc
+	{
+		return m_version == UNKNOWN_VERS;
+	}
 
 	/** Tests two versions for equality, according to the selected match mode.
 	*/
 	bool matches(Version other, VersionMatchMode mode = VersionMatchMode.standard)
-	const {
+	const scope @safe pure
+	{
 		if (this != other)
 			return false;
 
@@ -757,8 +773,8 @@
 		compared using SemVer semantics, while branches are compared
 		lexicographically.
 	*/
-	int opCmp(ref const Version other)
-	const {
+	int opCmp(scope ref const Version other) const scope @safe pure
+	{
 		if (isUnknown || other.isUnknown) {
 			throw new Exception("Can't compare unknown versions! (this: %s, other: %s)".format(this, other));
 		}
@@ -781,10 +797,16 @@
 		return compareVersions(m_version, other.m_version);
 	}
 	/// ditto
-	int opCmp(const Version other) const { return opCmp(other); }
+	int opCmp(scope const Version other) const scope @safe pure
+	{
+		return this.opCmp(other);
+	}
 
 	/// Returns the string representation of the version/branch.
-	string toString() const { return m_version; }
+	string toString() const return scope @safe pure nothrow @nogc
+	{
+		return m_version;
+	}
 }
 
 /// A range of versions that are acceptable
@@ -796,7 +818,7 @@
 	bool m_inclusiveB = true; // B comparison < (true) or <= (false)
 
 	///
-	public int opCmp (const VersionRange o) const @safe
+	public int opCmp (scope const VersionRange o) const scope @safe
 	{
 		if (m_inclusiveA != o.m_inclusiveA) return m_inclusiveA < o.m_inclusiveA ? -1 : 1;
 		if (m_inclusiveB != o.m_inclusiveB) return m_inclusiveB < o.m_inclusiveB ? -1 : 1;
diff --git a/source/dub/semver.d b/source/dub/semver.d
index c04a9c5..674b324 100644
--- a/source/dub/semver.d
+++ b/source/dub/semver.d
@@ -24,7 +24,7 @@
 /**
 	Validates a version string according to the SemVer specification.
 */
-bool isValidVersion(string ver)
+bool isValidVersion(scope string ver)
 pure @nogc {
 	// NOTE: this is not by spec, but to ensure sane input
 	if (ver.length > 256) return false;
@@ -101,7 +101,7 @@
 /**
 	Determines if a given valid SemVer version has a pre-release suffix.
 */
-bool isPreReleaseVersion(string ver) pure @nogc
+bool isPreReleaseVersion(scope string ver) pure @nogc nothrow
 in { assert(isValidVersion(ver)); }
 do {
 	foreach (i; 0 .. 2) {
@@ -134,16 +134,30 @@
 		Returns a negative number if `a` is a lower version than `b`, `0` if they are
 		equal, and a positive number otherwise.
 */
-int compareVersions(string a, string b)
+int compareVersions(scope string a, scope string b)
 pure @nogc {
+	// This needs to be a nested function as we can't pass local scope
+	// variables by `ref`
+	int compareNumber() @safe pure @nogc {
+		int res = 0;
+		while (true) {
+			if (a[0] != b[0] && res == 0) res = a[0] - b[0];
+			a = a[1 .. $]; b = b[1 .. $];
+			auto aempty = !a.length || (a[0] < '0' || a[0] > '9');
+			auto bempty = !b.length || (b[0] < '0' || b[0] > '9');
+			if (aempty != bempty) return bempty - aempty;
+			if (aempty) return res;
+		}
+	}
+
 	// compare a.b.c numerically
-	if (auto ret = compareNumber(a, b)) return ret;
+	if (auto ret = compareNumber()) return ret;
 	assert(a[0] == '.' && b[0] == '.');
 	a = a[1 .. $]; b = b[1 .. $];
-	if (auto ret = compareNumber(a, b)) return ret;
+	if (auto ret = compareNumber()) return ret;
 	assert(a[0] == '.' && b[0] == '.');
 	a = a[1 .. $]; b = b[1 .. $];
-	if (auto ret = compareNumber(a, b)) return ret;
+	if (auto ret = compareNumber()) return ret;
 
 	// give precedence to non-prerelease versions
 	bool apre = a.length > 0 && a[0] == '-';
@@ -314,7 +328,7 @@
 	assert("1.0.0-pre.release+meta" == expandVersion("1-pre.release+meta"));
 }
 
-private int compareIdentifier(ref string a, ref string b)
+private int compareIdentifier(scope ref string a, scope ref string b)
 pure @nogc {
 	bool anumber = true;
 	bool bnumber = true;
@@ -344,20 +358,7 @@
 	}
 }
 
-private int compareNumber(ref string a, ref string b)
-pure @nogc {
-	int res = 0;
-	while (true) {
-		if (a[0] != b[0] && res == 0) res = a[0] - b[0];
-		a = a[1 .. $]; b = b[1 .. $];
-		auto aempty = !a.length || (a[0] < '0' || a[0] > '9');
-		auto bempty = !b.length || (b[0] < '0' || b[0] > '9');
-		if (aempty != bempty) return bempty - aempty;
-		if (aempty) return res;
-	}
-}
-
-private bool isValidIdentifierChain(string str, bool allow_leading_zeros = false)
+private bool isValidIdentifierChain(scope string str, bool allow_leading_zeros = false)
 pure @nogc {
 	if (str.length == 0) return false;
 	while (str.length) {
@@ -370,7 +371,7 @@
 	return true;
 }
 
-private bool isValidIdentifier(string str, bool allow_leading_zeros = false)
+private bool isValidIdentifier(scope string str, bool allow_leading_zeros = false)
 pure @nogc {
 	if (str.length < 1) return false;
 
@@ -394,7 +395,7 @@
 }
 
 private bool isValidNumber(string str)
-pure @nogc {
+pure @nogc nothrow {
 	if (str.length < 1) return false;
 	foreach (ch; str)
 		if (ch < '0' || ch > '9')
@@ -406,7 +407,7 @@
 	return true;
 }
 
-private ptrdiff_t indexOfAny(string str, in char[] chars)
+private ptrdiff_t indexOfAny(scope string str, in char[] chars)
 pure @nogc {
 	ptrdiff_t ret = -1;
 	foreach (ch; chars) {