go/printer: Fprint crashes with unexpected parenthesized expression panic #69206
Description
Reproducer:
func TestPrinterPanic(t *testing.T) {
const src = `package A
type A[C((D)),] struct{}
`
fs := token.NewFileSet()
f, err := parser.ParseFile(fs, "test.go", src, parser.ParseComments|parser.SkipObjectResolution)
if err != nil {
t.Fatal(err)
}
Fprint(io.Discard, fs, f) // panic: unexpected parenthesized expression.
}panic: unexpected parenthesized expression [recovered]
panic: unexpected parenthesized expression
goroutine 6 [running]:
testing.tRunner.func1.2({0x586300, 0x5fbc80})
testing/testing.go:1706 +0x230
testing.tRunner.func1()
testing/testing.go:1709 +0x35e
panic({0x586300?, 0x5fbc80?})
runtime/panic.go:785 +0x132
go/printer.combinesWithName({0x5fe0b8?, 0xc0000700e0?})
go/printer/nodes.go:416 +0x5c
go/printer.(*printer).parameters(0xc0000a21a0, 0xc0000845a0, 0x2)
go/printer/nodes.go:383 +0xa3d
go/printer.(*printer).spec(0xc0000a21a0, {0x5fe358?, 0xc000090a40}, 0x1, 0x1?)
go/printer/nodes.go:1719 +0x419
go/printer.(*printer).genDecl(0xc0000a21a0, 0xc000090b00)
go/printer/nodes.go:1777 +0x407
go/printer.(*printer).decl(0xc0000a21a0?, {0x5fdfc8?, 0xc000090b00?})
go/printer/nodes.go:1945 +0x51
go/printer.(*printer).declList(0xc0000a21a0, {0xc000020460?, 0xc000070060?, 0x0?})
go/printer/nodes.go:1990 +0x39
go/printer.(*printer).file(0xc0000a21a0, 0xc000080280)
go/printer/nodes.go:1999 +0x16f
go/printer.(*printer).printNode(0xc0000a21a0, {0x592020?, 0xc000080280?})
go/printer/printer.go:1172 +0x16a
go/printer.(*Config).fprint(0xc0000c9f20, {0x5fcea0, 0x72a020}, 0x586300?, {0x592020, 0xc000080280}, 0x4dabc0?)
go/printer/printer.go:1364 +0xab
go/printer.(*Config).Fprint(...)
go/printer/printer.go:1424
go/printer.Fprint(...)
go/printer/printer.go:1432