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[dev.typeparams] cmd/compile/internal/types2: report constant overflow in binary ops

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This is the go.types changes of https://golang.org/cl/271706
ported to types2.

Also: Fixed a bug in the go/types version (was using the
wrong position in the error message).

Change-Id: I798b80243a66f0be5b943a6951d7a1ff769abca2
Reviewed-on: https://go-review.googlesource.com/c/go/+/271806
Trust: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
This commit is contained in:
Robert Griesemer 2020-11-19 17:49:05 -08:00
parent b1ae0a0646
commit 8fbdacf64c
4 changed files with 24 additions and 4 deletions
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12
src/cmd/compile/internal/types2/expr.go
View File

@ -897,7 +897,7 @@ var binaryOpPredicates = opPredicates{
}
// The binary expression e may be nil. It's passed in for better error messages only.
func (check *Checker) binary(x *operand, e *syntax.Operation, lhs, rhs syntax.Expr, op syntax.Operator) {
func (check *Checker) binary(x *operand, e *syntax.Operation, lhs, rhs syntax.Expr, op syntax.Operator, opPos syntax.Pos) {
var y operand
check.expr(x, lhs)
@ -977,6 +977,14 @@ func (check *Checker) binary(x *operand, e *syntax.Operation, lhs, rhs syntax.Ex
tok = token.QUO_ASSIGN
}
x.val = constant.BinaryOp(xval, tok, yval)
// report error if valid operands lead to an invalid result
if xval.Kind() != constant.Unknown && yval.Kind() != constant.Unknown && x.val.Kind() == constant.Unknown {
// TODO(gri) We should report exactly what went wrong. At the
// moment we don't have the (go/constant) API for that.
// See also TODO in go/constant/value.go.
check.errorf(opPos, "constant result is not representable")
// TODO(gri) Should we mark operands with unknown values as invalid?
}
// Typed constants must be representable in
// their type after each constant operation.
if isTyped(typ) {
@ -1791,7 +1799,7 @@ func (check *Checker) exprInternal(x *operand, e syntax.Expr, hint Type) exprKin
}
// binary expression
check.binary(x, e, e.X, e.Y, e.Op)
check.binary(x, e, e.X, e.Y, e.Op, e.Y.Pos()) // TODO(gri) should have OpPos here (like in go/types)
if x.mode == invalid {
goto Error
}

12
src/cmd/compile/internal/types2/fixedbugs/issue20583.src Normal file
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@ -0,0 +1,12 @@
// Copyright 2020 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package issue20583
const (
_ = 6e886451608 /* ERROR malformed constant */ /2
_ = 6e886451608i /* ERROR malformed constant */ /2
_ = 0 * 1e+1000000000 // ERROR malformed constant
x = 1e100000000
_ = x*x*x*x*x*x*x /* ERROR not representable */ // TODO(gri) this error should be at the last *
)

2
src/cmd/compile/internal/types2/stmt.go
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@ -396,7 +396,7 @@ func (check *Checker) stmt(ctxt stmtContext, s syntax.Stmt) {
}
var x operand
check.binary(&x, nil, lhs[0], rhs[0], s.Op)
check.binary(&x, nil, lhs[0], rhs[0], s.Op, rhs[0].Pos()) // TODO(gri) should have TokPos here (like in go/types)
if x.mode == invalid {
return
}

2
src/go/types/expr.go
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@ -890,7 +890,7 @@ func (check *Checker) binary(x *operand, e *ast.BinaryExpr, lhs, rhs ast.Expr, o
// TODO(gri) We should report exactly what went wrong. At the
// moment we don't have the (go/constant) API for that.
// See also TODO in go/constant/value.go.
check.errorf(atPos(e.OpPos), _InvalidConstVal, "constant result is not representable")
check.errorf(atPos(opPos), _InvalidConstVal, "constant result is not representable")
// TODO(gri) Should we mark operands with unknown values as invalid?
}
// Typed constants must be representable in