diff --git a/source/dub/compilers/buildsettings.d b/source/dub/compilers/buildsettings.d
index 2d821a4..c874c88 100644
--- a/source/dub/compilers/buildsettings.d
+++ b/source/dub/compilers/buildsettings.d
@@ -298,6 +298,7 @@
 		static if (__VERSION__ >= 2067) {
 			@ignore BitFlags!BuildOption values;
 			this(BuildOption opt) { values = opt; }
+			this(BitFlags!BuildOption v) { values = v; }
 			deprecated("Use BuildOption.* instead.") {
 				enum none = BuildOption.none;
 				enum debugMode = BuildOption.debugMode;
@@ -342,3 +343,21 @@
 
 		alias values this;
 	}
+
+/**
+	All build options that will be inherited upwards in the dependency graph
+
+	Build options in this category fulfill one of the following properties:
+	$(UL
+		$(LI The option affects the semantics of the generated code)
+		$(LI The option affects if a certain piece of code is valid or not)
+		$(LI The option enabled meta information in dependent projects that are useful for the dependee (e.g. debug information))
+	)
+*/
+enum BuildOptions inheritedBuildOptions = BuildOption.debugMode | BuildOption.releaseMode
+	| BuildOption.coverage | BuildOption.debugInfo | BuildOption.debugInfoC
+	| BuildOption.alwaysStackFrame | BuildOption.stackStomping | BuildOption.inline
+	| BuildOption.noBoundsCheck | BuildOption.profile | BuildOption.ignoreUnknownPragmas
+	| BuildOption.syntaxOnly | BuildOption.warnings	| BuildOption.warningsAsErrors
+	| BuildOption.ignoreDeprecations | BuildOption.deprecationWarnings
+	| BuildOption.deprecationErrors | BuildOption.property | BuildOption.profileGC;
diff --git a/source/dub/generators/generator.d b/source/dub/generators/generator.d
index 541efd6..d4ac442 100644
--- a/source/dub/generators/generator.d
+++ b/source/dub/generators/generator.d
@@ -219,7 +219,7 @@
 			targetbs.add(settings.buildSettings);
 
 			// add build type settings and convert plain DFLAGS to build options
-			m_project.addBuildTypeSettings(targetbs, settings.platform, settings.buildType);
+			m_project.addBuildTypeSettings(targetbs, settings.platform, settings.buildType, pack is m_project.rootPackage);
 			settings.compiler.extractBuildOptions(targetbs);
 
 			enforce (generates_binary || pack !is m_project.rootPackage || (targetbs.options & BuildOption.syntaxOnly),
@@ -236,7 +236,7 @@
 		auto ti = &targets[target];
 		ti.buildSettings.addVersions(root_settings.versions);
 		ti.buildSettings.addDebugVersions(root_settings.debugVersions);
-		ti.buildSettings.addOptions(root_settings.options);
+		ti.buildSettings.addOptions(BuildOptions(root_settings.options & inheritedBuildOptions));
 
 		// special support for overriding string imports in parent packages
 		// this is a candidate for deprecation, once an alternative approach
diff --git a/source/dub/project.d b/source/dub/project.d
index a83bf26..fa902e7 100644
--- a/source/dub/project.d
+++ b/source/dub/project.d
@@ -530,12 +530,20 @@
 		}
 	}
 
-	void addBuildTypeSettings(ref BuildSettings dst, in BuildPlatform platform, string build_type)
+	void addBuildTypeSettings(ref BuildSettings dst, in BuildPlatform platform, string build_type, bool for_root_package = true)
 	{
 		bool usedefflags = !(dst.requirements & BuildRequirement.noDefaultFlags);
 		if (usedefflags) {
 			BuildSettings btsettings;
 			m_rootPackage.addBuildTypeSettings(btsettings, platform, build_type);
+			
+			if (!for_root_package) {
+				// don't propagate unittest switch to dependencies, as dependent
+				// unit tests aren't run anyway and the additional code may
+				// cause linking to fail on Windows (issue #640)
+				btsettings.removeOptions(BuildOption.unittests);
+			}
+
 			processVars(dst, this, m_rootPackage, btsettings);
 		}
 	}