diff --git a/lib/BasicEvaluatedExpression.js b/lib/BasicEvaluatedExpression.js
index 0b82b15d5dc..defa4560539 100644
--- a/lib/BasicEvaluatedExpression.js
+++ b/lib/BasicEvaluatedExpression.js
@@ -55,6 +55,14 @@ class BasicEvaluatedExpression {
 		return Object.prototype.hasOwnProperty.call(this, "quasis");
 	}
 
+	isTruthy() {
+		return this.truthy;
+	}
+
+	isFalsy() {
+		return this.falsy;
+	}
+
 	asBool() {
 		if(this.truthy) return true;
 		else if(this.falsy) return false;
diff --git a/lib/Parser.js b/lib/Parser.js
index 1bfcc7c7ced..16592aefde1 100644
--- a/lib/Parser.js
+++ b/lib/Parser.js
@@ -242,6 +242,10 @@ class Parser extends Tapable {
 				if(!argument) return;
 				if(argument.isBoolean()) {
 					return new BasicEvaluatedExpression().setBoolean(!argument.bool).setRange(expr.range);
+				} else if(argument.isTruthy()) {
+					return new BasicEvaluatedExpression().setBoolean(false).setRange(expr.range);
+				} else if(argument.isFalsy()) {
+					return new BasicEvaluatedExpression().setBoolean(true).setRange(expr.range);
 				} else if(argument.isString()) {
 					return new BasicEvaluatedExpression().setBoolean(!argument.string).setRange(expr.range);
 				} else if(argument.isNumber()) {
diff --git a/test/configCases/plugins/define-plugin/index.js b/test/configCases/plugins/define-plugin/index.js
index bb86ef24852..1d78a3fa332 100644
--- a/test/configCases/plugins/define-plugin/index.js
+++ b/test/configCases/plugins/define-plugin/index.js
@@ -98,3 +98,11 @@ it("should not explode on recursive statements", function() {
 		wurst; // <- is recursivly defined in config
 	}).should.throw("suppe is not defined");
 });
+
+it("should evaluate composed expressions (issue 5100)", function() {
+	if(!module.hot && process.env.DEFINED_NESTED_KEY_STRING === "string") {
+		// ok
+	} else {
+		require("fail");
+	}
+})