demangle: an omitted subobject selector is 0

Author: ianlancetaylor

cases_test.go

@@ -30176,7 +30176,6 @@ var casesExpectedFailures = map[string]bool{
 	"_ZN1XIZ1fIiEvOT_EUlOT_DpT0_E_EclIJEEEvDpT_":                                                    true,
 	"_ZN1XIZ1fIiEvOT_EUlS2_DpT0_E_EclIJEEEvDpT_":                                                    true,
 	"_ZZZZN6abcdef9abcdefghi29abcdefabcdefabcdefabcefabcdef27xxxxxxxxxxxxxxxxxxxxxxxxxxxEN4absl8DurationERKNSt3__u12basic_stringIcNS4_11char_traitsIcEENS4_9allocatorIcEEEEPNS1_19yyyyyyyyyyyyyyyyyyyEENK3$_5clEvENKUlvE_clEvE6zzzzzz": true,
-	"_Z1fIXtl1BadsoiL_Z6nestedE_EEEEvv":            true,
 	"_Z1fIXtl1BcvPiplcvPcadL_Z7derivedELl16EEEEvv": true,
 	"_Z1fIXtl1Edi1nLi42EEEEvv":                     true,
 	"_Z1h1XIJZ1fIiEDaOT_E1AZ1gIdEDaS2_E1BEE":       true,

demangle.go

@@ -2219,7 +2219,10 @@ func (st *state) subobject() AST {
 	var selectors []int
 	for len(st.str) > 0 && st.str[0] == '_' {
 		st.advance(1)
-		selector := st.number()
+		selector := 0
+		if len(st.str) > 0 && (st.str[0] == 'n' || isDigit(st.str[0])) {
+			selector = st.number()
+		}
 		selectors = append(selectors, selector)
 	}
 	pastEnd := false