diff options
Diffstat (limited to 'src/cmd/compile/internal/types2/decl.go')
| -rw-r--r-- | src/cmd/compile/internal/types2/decl.go | 23 |
1 files changed, 20 insertions, 3 deletions
diff --git a/src/cmd/compile/internal/types2/decl.go b/src/cmd/compile/internal/types2/decl.go index 342e1090de5..d7a33546aa4 100644 --- a/src/cmd/compile/internal/types2/decl.go +++ b/src/cmd/compile/internal/types2/decl.go @@ -514,11 +514,26 @@ func (check *Checker) varDecl(obj *Var, lhs []*Var, typ, init syntax.Expr) { check.initVars(lhs, []syntax.Expr{init}, nopos) } +// isImportedConstraint reports whether typ is an imported type constraint. +func (check *Checker) isImportedConstraint(typ Type) bool { + named, _ := typ.(*Named) + if named == nil || named.obj.pkg == check.pkg || named.obj.pkg == nil { + return false + } + u, _ := named.under().(*Interface) + return u != nil && u.IsConstraint() +} + func (check *Checker) typeDecl(obj *TypeName, tdecl *syntax.TypeDecl, def *Named) { assert(obj.typ == nil) + var rhs Type check.later(func() { check.validType(obj.typ, nil) + // If typ is local, an error was already reported where typ is specified/defined. + if check.isImportedConstraint(rhs) && !check.allowVersion(check.pkg, 1, 18) { + check.errorf(tdecl.Type.Pos(), "using type constraint %s requires go1.18 or later", rhs) + } }) alias := tdecl.Alias @@ -540,7 +555,8 @@ func (check *Checker) typeDecl(obj *TypeName, tdecl *syntax.TypeDecl, def *Named } obj.typ = Typ[Invalid] - obj.typ = check.anyType(tdecl.Type) + rhs = check.anyType(tdecl.Type) + obj.typ = rhs return } @@ -555,8 +571,9 @@ func (check *Checker) typeDecl(obj *TypeName, tdecl *syntax.TypeDecl, def *Named } // determine underlying type of named - named.fromRHS = check.definedType(tdecl.Type, named) - assert(named.fromRHS != nil) + rhs = check.definedType(tdecl.Type, named) + assert(rhs != nil) + named.fromRHS = rhs // The underlying type of named may be itself a named type that is // incomplete: // |