diff --git a/lib/Less/Tree.php b/lib/Less/Tree.php
index f5ec816d..1a726cd6 100644
--- a/lib/Less/Tree.php
+++ b/lib/Less/Tree.php
@@ -64,6 +64,63 @@ public static function outputRuleset( $output, $rules ) {
 	public function accept( $visitor ) {
 	}
 
+	/**
+	 * @param Less_Tree $a
+	 * @param Less_Tree $b
+	 * @return int|null
+	 * @see less-2.5.3.js#Node.compare
+	 */
+	public static function nodeCompare( $a, $b ) {
+		// Less_Tree subclasses that implement compare() are:
+		// Anonymous, Color, Dimension, Keyword, Quoted, Unit
+		if ( $b instanceof Less_Tree_Quoted || $b instanceof Less_Tree_Anonymous ) {
+			// for "symmetric results" force toCSS-based comparison via b.compare()
+			// of Quoted or Anonymous if either value is one of those
+			return -$b->compare( $a );
+		} elseif ( $a instanceof Less_Tree_Anonymous || $a instanceof Less_Tree_Color
+			|| $a instanceof Less_Tree_Dimension || $a instanceof Less_Tree_Keyword
+			|| $a instanceof Less_Tree_Quoted || $a instanceof Less_Tree_Unit
+		) {
+			return $a->compare( $b );
+		} elseif ( get_class( $a ) !== get_class( $b ) ) {
+			return null;
+		}
+
+		// Less_Tree subclasses that have an array value: Less_Tree_Expression, Less_Tree_Value
+		// @phan-suppress-next-line PhanUndeclaredProperty
+		$aval = $a->value ?? [];
+		// @phan-suppress-next-line PhanUndeclaredProperty
+		$bval = $b->value ?? [];
+		if ( !( $a instanceof Less_Tree_Expression || $a instanceof Less_Tree_Value ) ) {
+			return $aval === $bval ? 0 : null;
+		}
+		if ( count( $aval ) !== count( $bval ) ) {
+			return null;
+		}
+		foreach ( $aval as $i => $item ) {
+			if ( self::nodeCompare( $item, $bval[$i] ) !== 0 ) {
+				return null;
+			}
+		}
+		return 0;
+	}
+
+	/**
+	 * @param string|float|int $a
+	 * @param string|float|int $b
+	 * @return int|null
+	 * @see less-2.5.3.js#Node.numericCompare
+	 */
+	public static function numericCompare( $a, $b ) {
+		return $a < $b ? -1
+			: ( $a === $b ? 0
+				: ( $a > $b ? 1
+					// NAN is not greater, less, or equal
+					: null
+				)
+			);
+	}
+
 	public static function ReferencedArray( $rules ) {
 		foreach ( $rules as $rule ) {
 			if ( method_exists( $rule, 'markReferenced' ) ) {
diff --git a/lib/Less/Tree/Anonymous.php b/lib/Less/Tree/Anonymous.php
index 381b808e..228d1039 100644
--- a/lib/Less/Tree/Anonymous.php
+++ b/lib/Less/Tree/Anonymous.php
@@ -31,19 +31,13 @@ public function compile( $env ) {
 		return new self( $this->value, $this->index, $this->currentFileInfo, $this->mapLines );
 	}
 
+	/**
+	 * @param Less_Tree|mixed $x
+	 * @return int|null
+	 * @see less-2.5.3.js#Anonymous.prototype.compare
+	 */
 	public function compare( $x ) {
-		if ( !is_object( $x ) ) {
-			return -1;
-		}
-
-		$left = $this->toCSS();
-		$right = $x->toCSS();
-
-		if ( $left === $right ) {
-			return 0;
-		}
-
-		return $left < $right ? -1 : 1;
+		return ( is_object( $x ) && $this->toCSS() === $x->toCSS() ) ? 0 : null;
 	}
 
 	public function isRulesetLike() {
diff --git a/lib/Less/Tree/Color.php b/lib/Less/Tree/Color.php
index e28dcb5c..0a1fedd6 100644
--- a/lib/Less/Tree/Color.php
+++ b/lib/Less/Tree/Color.php
@@ -191,15 +191,20 @@ public function toARGB() {
 		return $this->toHex( $argb );
 	}
 
+	/**
+	 * @param mixed $x
+	 * @return int|null
+	 * @see less-2.5.3.js#Color.prototype.compare
+	 */
 	public function compare( $x ) {
-		if ( !property_exists( $x, 'rgb' ) ) {
+		if ( !$x instanceof self ) {
 			return -1;
 		}
 
 		return ( $x->rgb[0] === $this->rgb[0] &&
 			$x->rgb[1] === $this->rgb[1] &&
 			$x->rgb[2] === $this->rgb[2] &&
-			$x->alpha === $this->alpha ) ? 0 : -1;
+			$x->alpha === $this->alpha ) ? 0 : null;
 	}
 
 	public function toHex( $v ) {
diff --git a/lib/Less/Tree/Condition.php b/lib/Less/Tree/Condition.php
index dc230d66..073605fe 100644
--- a/lib/Less/Tree/Condition.php
+++ b/lib/Less/Tree/Condition.php
@@ -23,6 +23,11 @@ public function accept( $visitor ) {
 		$this->rvalue = $visitor->visitObj( $this->rvalue );
 	}
 
+	/**
+	 * @param Less_Environment $env
+	 * @return bool
+	 * @see less-2.5.3.js#Condition.prototype.eval
+	 */
 	public function compile( $env ) {
 		$a = $this->lvalue->compile( $env );
 		$b = $this->rvalue->compile( $env );
@@ -37,26 +42,18 @@ public function compile( $env ) {
 				break;
 
 			default:
-				if ( Less_Parser::is_method( $a, 'compare' ) ) {
-					$result = $a->compare( $b );
-				} elseif ( Less_Parser::is_method( $b, 'compare' ) ) {
-					$result = $b->compare( $a );
-				} else {
-					throw new Less_Exception_Compiler( 'Unable to perform comparison', null, $this->index );
-				}
-
-				switch ( $result ) {
+				switch ( Less_Tree::nodeCompare( $a, $b ) ) {
 					case -1:
 						$result = $this->op === '<' || $this->op === '=<' || $this->op === '<=';
 						break;
-
 					case 0:
 						$result = $this->op === '=' || $this->op === '>=' || $this->op === '=<' || $this->op === '<=';
 						break;
-
 					case 1:
 						$result = $this->op === '>' || $this->op === '>=';
 						break;
+					default:
+						$result = false;
 				}
 				break;
 		}
diff --git a/lib/Less/Tree/Dimension.php b/lib/Less/Tree/Dimension.php
index f4e87a50..33d8ebc8 100644
--- a/lib/Less/Tree/Dimension.php
+++ b/lib/Less/Tree/Dimension.php
@@ -110,32 +110,28 @@ public function operate( $op, $other ) {
 		return new self( $value, $unit );
 	}
 
+	/**
+	 * @param Less_Tree $other
+	 * @return int|null
+	 * @see less-2.5.3.js#Dimension.prototype.compare
+	 */
 	public function compare( $other ) {
-		if ( $other instanceof self ) {
-
-			if ( $this->unit->isEmpty() || $other->unit->isEmpty() ) {
-				$a = $this;
-				$b = $other;
-			} else {
-				$a = $this->unify();
-				$b = $other->unify();
-				if ( $a->unit->compare( $b->unit ) !== 0 ) {
-					return -1;
-				}
-			}
-			$aValue = $a->value;
-			$bValue = $b->value;
+		if ( !$other instanceof self ) {
+			return null;
+		}
 
-			if ( $bValue > $aValue ) {
-				return -1;
-			} elseif ( $bValue < $aValue ) {
-				return 1;
-			} else {
-				return 0;
-			}
+		if ( $this->unit->isEmpty() || $other->unit->isEmpty() ) {
+			$a = $this;
+			$b = $other;
 		} else {
-			return -1;
+			$a = $this->unify();
+			$b = $other->unify();
+			if ( $a->unit->compare( $b->unit ) !== 0 ) {
+				return null;
+			}
 		}
+
+		return Less_Tree::numericCompare( $a->value, $b->value );
 	}
 
 	public function unify() {
diff --git a/lib/Less/Tree/Quoted.php b/lib/Less/Tree/Quoted.php
index 7120160b..90335f8f 100644
--- a/lib/Less/Tree/Quoted.php
+++ b/lib/Less/Tree/Quoted.php
@@ -61,18 +61,19 @@ public function compile( $env ) {
 		return new self( $this->quote . $r . $this->quote, $r, $this->escaped, $this->index, $this->currentFileInfo );
 	}
 
-	public function compare( $x ) {
-		if ( !Less_Parser::is_method( $x, 'toCSS' ) ) {
-			return -1;
-		}
-
-		$left = $this->toCSS();
-		$right = $x->toCSS();
-
-		if ( $left === $right ) {
-			return 0;
+	/**
+	 * @param mixed $other
+	 * @return int|null
+	 * @see less-2.5.3.js#Quoted.prototype.compare
+	 */
+	public function compare( $other ) {
+		if ( $other instanceof self && !$this->escaped && !$other->escaped ) {
+			return Less_Tree::numericCompare( $this->value, $other->value );
+		} else {
+			return (
+				Less_Parser::is_method( $other, 'toCSS' )
+				&& $this->toCSS() === $other->toCSS()
+			) ? 0 : null;
 		}
-
-		return $left < $right ? -1 : 1;
 	}
 }
diff --git a/test/Fixtures/less.php/css/T357160-quoted-compare.css b/test/Fixtures/less.php/css/T357160-quoted-compare.css
new file mode 100644
index 00000000..04850b43
--- /dev/null
+++ b/test/Fixtures/less.php/css/T357160-quoted-compare.css
@@ -0,0 +1,8 @@
+double {
+  background: red;
+  background: blue;
+}
+single {
+  background: red;
+  background: blue;
+}
diff --git a/test/Fixtures/less.php/less/T357160-quoted-compare.less b/test/Fixtures/less.php/less/T357160-quoted-compare.less
new file mode 100644
index 00000000..3ecccee9
--- /dev/null
+++ b/test/Fixtures/less.php/less/T357160-quoted-compare.less
@@ -0,0 +1,14 @@
+.test-mixin(@value) when (@value = "test") {
+  background: red;
+}
+
+.test-mixin(@value) when (@value = 'test') {
+  background: blue;
+}
+
+double {
+  .test-mixin("test")
+}
+single {
+  .test-mixin('test')
+}