diff options
Diffstat (limited to 'src/go/types/typexpr.go')
| -rw-r--r-- | src/go/types/typexpr.go | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/src/go/types/typexpr.go b/src/go/types/typexpr.go index af56297144..0143f53009 100644 --- a/src/go/types/typexpr.go +++ b/src/go/types/typexpr.go @@ -258,7 +258,7 @@ func (check *Checker) typInternal(e0 ast.Expr, def *Named) (T Type) { check.errorf(&x, _NotAType, "%s is not a type", &x) } - case *ast.IndexExpr, *ast.MultiIndexExpr: + case *ast.IndexExpr, *ast.IndexListExpr: ix := typeparams.UnpackIndexExpr(e) if !check.allowVersion(check.pkg, 1, 18) { check.softErrorf(inNode(e, ix.Lbrack), _Todo, "type instantiation requires go1.18 or later") @@ -412,6 +412,14 @@ func (check *Checker) instantiatedType(x ast.Expr, targsx []ast.Expr, def *Named // and returns the constant length >= 0, or a value < 0 // to indicate an error (and thus an unknown length). func (check *Checker) arrayLength(e ast.Expr) int64 { + // If e is an undeclared identifier, the array declaration might be an + // attempt at a parameterized type declaration with missing constraint. + // Provide a better error message than just "undeclared name: X". + if name, _ := e.(*ast.Ident); name != nil && check.lookup(name.Name) == nil { + check.errorf(name, _InvalidArrayLen, "undeclared name %s for array length", name.Name) + return -1 + } + var x operand check.expr(&x, e) if x.mode != constant_ { @@ -420,6 +428,7 @@ func (check *Checker) arrayLength(e ast.Expr) int64 { } return -1 } + if isUntyped(x.typ) || isInteger(x.typ) { if val := constant.ToInt(x.val); val.Kind() == constant.Int { if representableConst(val, check, Typ[Int], nil) { @@ -431,6 +440,7 @@ func (check *Checker) arrayLength(e ast.Expr) int64 { } } } + check.errorf(&x, _InvalidArrayLen, "array length %s must be integer", &x) return -1 } |