2 files changed, 26 insertions, 3 deletions
diff --git a/src/debug/gosym/symtab.go b/src/debug/gosym/symtab.go
index a84b7f6def..3be612e1df 100644
--- a/src/debug/gosym/symtab.go
+++ b/src/debug/gosym/symtab.go
@@ -35,13 +35,21 @@ func (s *Sym) Static() bool { return s.Type >= 'a' }
 // PackageName returns the package part of the symbol name,
 // or the empty string if there is none.
 func (s *Sym) PackageName() string {
-	pathend := strings.LastIndex(s.Name, "/")
+	name := s.Name
+
+	// A prefix of "type." and "go." is a compiler-generated symbol that doesn't belong to any package.
+	// See variable reservedimports in cmd/compile/internal/gc/subr.go
+	if strings.HasPrefix(name, "go.") || strings.HasPrefix(name, "type.") {
+		return ""
+	}
+
+	pathend := strings.LastIndex(name, "/")
 	if pathend < 0 {
 		pathend = 0
 	}
 
-	if i := strings.Index(s.Name[pathend:], "."); i != -1 {
-		return s.Name[:pathend+i]
+	if i := strings.Index(name[pathend:], "."); i != -1 {
+		return name[:pathend+i]
 	}
 	return ""
 }
diff --git a/src/debug/gosym/symtab_test.go b/src/debug/gosym/symtab_test.go
index 08e86336b8..b6ed8f554c 100644
--- a/src/debug/gosym/symtab_test.go
+++ b/src/debug/gosym/symtab_test.go
@@ -41,3 +41,18 @@ func TestRemotePackage(t *testing.T) {
 	assertString(t, fmt.Sprintf("receiver of %q", s1.Name), s1.ReceiverName(), "(*FlagSet)")
 	assertString(t, fmt.Sprintf("receiver of %q", s2.Name), s2.ReceiverName(), "")
 }
+
+func TestIssue29551(t *testing.T) {
+	symNames := []string{
+		"type..eq.[9]debug/elf.intName",
+		"type..hash.debug/elf.ProgHeader",
+		"type..eq.runtime._panic",
+		"type..hash.struct { runtime.gList; runtime.n int32 }",
+		"go.(*struct { sync.Mutex; math/big.table [64]math/big",
+	}
+
+	for _, symName := range symNames {
+		s := Sym{Name: symName}
+		assertString(t, fmt.Sprintf("package of %q", s.Name), s.PackageName(), "")
+	}
+}