fix parsing order

Author: navorite

packages/svelte/src/compiler/phases/1-parse/read/style.js

@@ -7,7 +7,7 @@ const REGEX_COMBINATOR_WHITESPACE = /^\s*(\+|~|>|\|\|)\s*/;
 const REGEX_COMBINATOR = /^(\+|~|>|\|\|)/;
 const REGEX_PERCENTAGE = /^\d+(\.\d+)?%/;
 const REGEX_NTH_OF =
-	/^\s*(even|odd|(\d+|\+?\d*n(\s*[+-]\s*\d+)?)|-\d*n(\s*\+\s*\d+))(\s*(?=[,)])|\s+of\s+)/;
+	/^\s*(even|odd|\+?(\d+|\d*n(\s*[+-]\s*\d+)?)|-\d*n(\s*\+\s*\d+))(\s*(?=[,)])|\s+of\s+)/;
 const REGEX_WHITESPACE_OR_COLON = /[\s:]/;
 const REGEX_BRACE_OR_SEMICOLON = /[{;]/;
 const REGEX_LEADING_HYPHEN_OR_DIGIT = /-?\d/;
@@ -278,6 +278,14 @@ function read_selector(parser, inside_pseudo_class = false) {
 				value,
 				flags
 			});
+		} else if (inside_pseudo_class && parser.match_regex(REGEX_NTH_OF)) {
+			// nth of matcher must come before combinator matcher to prevent collision else the '+' in '+2n-1' would be parsed as a combinator
+			children.push({
+				type: 'Nth',
+				value: /** @type {string} */ (parser.read(REGEX_NTH_OF)),
+				start,
+				end: parser.index
+			});
 		} else if (parser.match_regex(REGEX_COMBINATOR_WHITESPACE)) {
 			parser.allow_whitespace();
 			const start = parser.index;
@@ -295,13 +303,6 @@ function read_selector(parser, inside_pseudo_class = false) {
 				start,
 				end: parser.index
 			});
-		} else if (inside_pseudo_class && parser.match_regex(REGEX_NTH_OF)) {
-			children.push({
-				type: 'Nth',
-				value: /** @type {string} */ (parser.read(REGEX_NTH_OF)),
-				start,
-				end: parser.index
-			});
 		} else {
 			let name = read_identifier(parser);
 			if (parser.match('|')) {