diff --git a/CHANGELOG.md b/CHANGELOG.md
index 201738ff..f829f18e 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -9,6 +9,9 @@
 * Produce a better error message for style rules that are missing the closing
   `}`.
 
+* Produce a better error message for style rules and property declarations
+  within `@function` rules.
+
 ### Command-Line Interface
 
 * Passing a directory on the command line now compiles all Sass source files in
diff --git a/lib/src/parse/stylesheet.dart b/lib/src/parse/stylesheet.dart
index 388beb88..d6d88def 100644
--- a/lib/src/parse/stylesheet.dart
+++ b/lib/src/parse/stylesheet.dart
@@ -451,7 +451,7 @@ abstract class StylesheetParser extends Parser {
     // here should be mirrored there.
 
     var start = scanner.state;
-    scanner.expectChar($at);
+    scanner.expectChar($at, name: "@-rule");
     var name = interpolatedIdentifier();
     whitespace();
 
@@ -536,6 +536,23 @@ abstract class StylesheetParser extends Parser {
 
   /// Consumes an at-rule allowed within a function.
   Statement _functionAtRule() {
+    if (scanner.peekChar() != $at) {
+      var position = scanner.position;
+      Statement statement;
+      try {
+        statement = _declarationOrStyleRule();
+      } on SourceSpanFormatException catch (_) {
+        // If we can't parse a valid declaration or style rule, throw a more
+        // generic error message.
+        scanner.error("expected @-rule", position: position);
+      }
+
+      error(
+          "@function rules may not contain "
+          "${statement is StyleRule ? "style rules" : "declarations"}.",
+          statement.span);
+    }
+
     var start = scanner.state;
     switch (_plainAtRuleName()) {
       case "debug":
@@ -563,7 +580,7 @@ abstract class StylesheetParser extends Parser {
 
   /// Consumes an at-rule's name, with interpolation disallowed.
   String _plainAtRuleName() {
-    scanner.expectChar($at);
+    scanner.expectChar($at, name: "@-rule");
     var name = identifier();
     whitespace();
     return name;
diff --git a/pubspec.yaml b/pubspec.yaml
index 77d6401b..2bd3bcb6 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -1,5 +1,5 @@
 name: sass
-version: 1.17.0-dev
+version: 1.17.0
 description: A Sass implementation in Dart.
 author: Dart Team <misc@dartlang.org>
 homepage: https://github.com/sass/dart-sass