Fix stack overflow while simplifying calc expressions with nested functions

Fixes #166

Author: devongovett

src/lib.rs

@@ -5502,6 +5502,10 @@ mod tests {
     minify_test(".foo { width: calc(1cap + 2cap) }", ".foo{width:3cap}");
     minify_test(".foo { width: calc(1lh + 2lh) }", ".foo{width:3lh}");
     minify_test(".foo { width: calc(1x + 2x) }", ".foo{width:calc(1x + 2x)}");
+    minify_test(
+      ".foo { left: calc(50% - 100px + clamp(0px, calc(50vw - 50px), 100px)) }",
+      ".foo{left:calc(50% - 100px + clamp(0px,50vw - 50px,100px))}",
+    );
   }
 
   #[test]

src/values/calc.rs

@@ -394,6 +394,8 @@ impl<
       (Calc::Number(a), Calc::Number(b)) => Calc::Number(a + b),
       (Calc::Value(a), b) => (*a + V::from(b)).into(),
       (a, Calc::Value(b)) => (V::from(a) + *b).into(),
+      (Calc::Function(a), b) => Calc::Sum(Box::new(Calc::Function(a)), Box::new(b)),
+      (a, Calc::Function(b)) => Calc::Sum(Box::new(a), Box::new(Calc::Function(b))),
       (a, b) => (V::from(a) + V::from(b)).into(),
     }
   }

src/values/percentage.rs

@@ -298,9 +298,7 @@ impl<D: TryAdd<D> + Clone + std::cmp::PartialEq<CSSNumber> + std::cmp::PartialOr
     }
 
     match (a, b) {
-      (DimensionPercentage::Calc(a), DimensionPercentage::Calc(b)) => {
-        return DimensionPercentage::Calc(Box::new(*a + *b))
-      }
+      (DimensionPercentage::Calc(a), DimensionPercentage::Calc(b)) => DimensionPercentage::Calc(Box::new(*a + *b)),
       (DimensionPercentage::Calc(calc), b) => {
         if let Calc::Value(a) = *calc {
           a.add(b)