Crash when selector ends with escaped backslash and no whitespace

[connorskees]

dart-sass will crash on the following input:

\\{}

Stacktrace

Unexpected exception:
RangeError (end): Invalid value: Not in inclusive range 0..8: 9


dart:core                                               _StringBase.substring
package:sass/src/utils.dart 78                          trimAscii
package:sass/src/visitor/evaluate.dart 3153             _EvaluateVisitor._interpolationToValue
package:sass/src/visitor/evaluate.dart 1869             _EvaluateVisitor.visitStyleRule
package:sass/src/ast/sass/statement/style_rule.dart 30  StyleRule.accept
package:sass/src/visitor/evaluate.dart 938              _EvaluateVisitor.visitStylesheet
package:sass/src/visitor/evaluate.dart 746              _EvaluateVisitor._execute.<fn>
package:sass/src/visitor/evaluate.dart 3139             _EvaluateVisitor._withEnvironment
package:sass/src/visitor/evaluate.dart 716              _EvaluateVisitor._execute
package:sass/src/visitor/evaluate.dart 532              _EvaluateVisitor.run.<fn>
dart:async                                              runZoned
package:sass/src/evaluation_context.dart 57             withEvaluationContext
package:sass/src/visitor/evaluate.dart 525              _EvaluateVisitor.run
package:sass/src/visitor/evaluate.dart 97               evaluate
package:sass/src/compile.dart 151                       _compileStylesheet
package:sass/src/compile.dart 68                        compile
package:sass/src/executable/compile_stylesheet.dart 97  compileStylesheet
d:\a\dart-sass\dart-sass\bin\sass.dart 65               main