Ensure consistent order of custom properties with all property

Fixes #855

Cargo.toml

@@ -72,6 +72,7 @@ const-str = "0.3.1"
 pathdiff = "0.2.1"
 ahash = "0.8.7"
 paste = "1.0.12"
+indexmap = "2.2.6"
 # CLI deps
 atty = { version = "0.2", optional = true }
 clap = { version = "3.0.6", features = ["derive"], optional = true }

src/declaration.rs

@@ -1,7 +1,6 @@
 //! CSS declarations.
 
 use std::borrow::Cow;
-use std::collections::HashMap;
 use std::ops::Range;
 
 use crate::context::{DeclarationContext, PropertyHandlerContext};
@@ -41,6 +40,7 @@ use crate::values::string::CowArcStr;
 #[cfg(feature = "visitor")]
 use crate::visitor::Visit;
 use cssparser::*;
+use indexmap::IndexMap;
 
 /// A CSS declaration block.
 ///
@@ -518,7 +518,7 @@ pub(crate) struct DeclarationHandler<'i> {
   prefix: PrefixHandler,
   direction: Option<Direction>,
   unicode_bidi: Option<UnicodeBidi>,
-  custom_properties: HashMap<DashedIdent<'i>, usize>,
+  custom_properties: IndexMap<DashedIdent<'i>, usize>,
   decls: DeclarationList<'i>,
 }
 
@@ -609,7 +609,7 @@ impl<'i> DeclarationHandler<'i> {
           direction: self.direction.clone(),
           ..Default::default()
         };
-        for (key, index) in self.custom_properties.drain() {
+        for (key, index) in self.custom_properties.drain(..) {
           handler.custom_properties.insert(key, handler.decls.len());
           handler.decls.push(self.decls[index].clone());
         }

src/lib.rs

@@ -28355,5 +28355,9 @@ mod tests {
       ".foo { all: unset; background: var(--foo); }",
       ".foo{all:unset;background:var(--foo)}",
     );
+    minify_test(
+      ".foo {--bar:currentcolor; --foo:1.1em; all:unset}",
+      ".foo{--bar:currentcolor;--foo:1.1em;all:unset}",
+    );
   }
 }