fix(parser): fix crash when css variable property does not end with a semicolon (#3700)

Fixes #3698 #3373

packages/less/src/less/parser/parser.js

@@ -1551,7 +1551,7 @@ const Parser = function Parser(context, imports, fileInfo) {
 
                         // Custom property values get permissive parsing
                         if (name[0].value && name[0].value.slice(0, 2) === '--') {
-                            value = this.permissiveValue();
+                            value = this.permissiveValue(/[;}]/);
                         }
                         // Try to store values as anonymous
                         // If we need the value later we'll re-parse it in ruleset.parseValue

packages/test-data/css/_main/permissive-parse.css

@@ -35,3 +35,12 @@ foo[attr="blah"] {
   --value: a /* { ; } */;
   --comment-within: ( /* okay?; comment; */ );
 }
+.test-no-trailing-semicolon {
+  --value: foo;
+}
+.test-no-trailing-semicolon2 {
+  --value: foo;
+}
+.test-no-trailing-semicolon3 {
+  --value: foo;
+}

packages/test-data/less/_main/permissive-parse.less

@@ -47,4 +47,9 @@
 .test-rule-comment {
   --value: a/* { ; } */;
   --comment-within: ( /* okay?; comment; */ );
-}
+}
+.test-no-trailing-semicolon {
+  --value: foo
+}
+.test-no-trailing-semicolon2 {--value: foo}
+.test-no-trailing-semicolon3 { --value: foo }