diff options
Diffstat (limited to 'src/cmd/compile/internal/types2/union.go')
| -rw-r--r-- | src/cmd/compile/internal/types2/union.go | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/src/cmd/compile/internal/types2/union.go b/src/cmd/compile/internal/types2/union.go index 102826947c..85aa3d9104 100644 --- a/src/cmd/compile/internal/types2/union.go +++ b/src/cmd/compile/internal/types2/union.go @@ -43,12 +43,22 @@ func (t *Term) String() string { return (*term)(t).String() } // ---------------------------------------------------------------------------- // Implementation +// Avoid excessive type-checking times due to quadratic termlist operations. +const maxTermCount = 100 + +// parseUnion parses the given list of type expressions tlist as a union of +// those expressions. The result is a Union type, or Typ[Invalid] for some +// errors. func parseUnion(check *Checker, tlist []syntax.Expr) Type { var terms []*Term for _, x := range tlist { tilde, typ := parseTilde(check, x) if len(tlist) == 1 && !tilde { - return typ // single type + return typ // single type (optimization) + } + if len(terms) >= maxTermCount { + check.errorf(x, "cannot handle more than %d union terms (implementation limitation)", maxTermCount) + return Typ[Invalid] } terms = append(terms, NewTerm(tilde, typ)) } |