Fix a couple number hashing bugs

CHANGELOG.md

@@ -8,6 +8,9 @@
 * `var()` may now be passed in place of multiple arguments to `rgb()`, `rgba()`,
   `hsl()` and `hsla()`.
 
+* Fix some cases where equivalent numbers wouldn't count as the same keys in
+  maps.
+
 ### Dart API
 
 * Add a `functions` parameter to `compile()`, `compleString()`,

lib/src/util/number.dart

@@ -8,14 +8,23 @@ import '../value.dart';
 
 /// The maximum distance two Sass numbers are allowed to be from one another
 /// before they're considered different.
-final epsilon = 1 / (math.pow(10, SassNumber.precision));
+final epsilon = 1 / math.pow(10, SassNumber.precision);
+
+/// `epsilon / 2`, cached since [math.pow] may not be computed at compile-time
+/// and thus this probably won't be constant-folded.
+final _epsilonOver2 = epsilon / 2;
 
 /// Returns whether [number1] and [number2] are equal within [epsilon].
 bool fuzzyEquals(num number1, num number2) =>
     (number1 - number2).abs() < epsilon;
 
 /// Returns a hash code for [number] that matches [fuzzyEquals].
-int fuzzyHashCode(num number) => (number % epsilon).hashCode;
+int fuzzyHashCode(num number) {
+  var remainder = number % epsilon;
+  var truncated = number - remainder;
+  if (remainder >= _epsilonOver2) truncated += epsilon;
+  return truncated.hashCode;
+}
 
 /// Returns whether [number1] is less than [number2], and not [fuzzyEquals].
 bool fuzzyLessThan(num number1, num number2) =>

lib/src/value/number.dart

@@ -612,7 +612,7 @@ class SassNumber extends Value {
         var innerMap = _conversions[unit];
         return innerMap == null
             ? multiplier
-            : multiplier * innerMap.values.first;
+            : multiplier / innerMap.values.first;
       });
 
   /// Throws a [SassScriptException] with the given [message].