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cmd/compile/internal/types2: delay recording types of untyped operands when checking against type parameters

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Don't eagerly record the target type for an untyped operand if the
target type is just one of possibly many types in the type list of
a type parameter. Instead, record expression type only after we
checked that all types in the type list are ok.

Also, update assertion in Checker.recordTypeAndValue since (currently),
a type parameter is not considered a const type. We may change that,
eventually.

This is a temporary (but working) solution. Eventually we should
copy the approach taken in go/types.

Fixes #45096.

Change-Id: Icf61ee893aca6ead32bfc45ee5831572e672357b
Reviewed-on: https://go-review.googlesource.com/c/go/+/302755
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
This commit is contained in:
Robert Griesemer 2021-03-17 16:59:47 -07:00
parent 2583c1b4df
commit 51e4bb236c
3 changed files with 16 additions and 7 deletions
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3
src/cmd/compile/internal/types2/api_test.go
View File

@ -337,6 +337,9 @@ func TestTypesInfo(t *testing.T) {
// instantiated types must be sanitized
{`package g0; type t[P any] int; var x struct{ f t[int] }; var _ = x.f`, `x.f`, `g0.t[int]`},
// issue 45096
{`package issue45096; func _[T interface{ type int8, int16, int32 }](x T) { _ = x < 0 }`, `0`, `T₁`},
}
for _, test := range tests {

4
src/cmd/compile/internal/types2/check.go
View File

@ -335,7 +335,9 @@ func (check *Checker) recordTypeAndValue(x syntax.Expr, mode operandMode, typ Ty
}
if mode == constant_ {
assert(val != nil)
assert(typ == Typ[Invalid] || isConstType(typ))
// We check is(typ, IsConstType) here as constant expressions may be
// recorded as type parameters.
assert(typ == Typ[Invalid] || is(typ, IsConstType))
}
if m := check.Types; m != nil {
m[x] = TypeAndValue{mode, typ, val}

16
src/cmd/compile/internal/types2/expr.go
View File

@ -628,7 +628,7 @@ func (check *Checker) convertUntyped(x *operand, target Type) {
for _, t := range unpack(types) {
x := *x // make a copy; convertUntypedInternal modifies x
check.convertUntypedInternal(&x, t)
check.convertUntypedInternal(&x, t, false)
if x.mode == invalid {
goto Error
}
@ -639,7 +639,7 @@ func (check *Checker) convertUntyped(x *operand, target Type) {
return
}
check.convertUntypedInternal(x, target)
check.convertUntypedInternal(x, target, true)
return
Error:
@ -649,7 +649,7 @@ Error:
}
// convertUntypedInternal should only be called by convertUntyped.
func (check *Checker) convertUntypedInternal(x *operand, target Type) {
func (check *Checker) convertUntypedInternal(x *operand, target Type, update bool) {
assert(isTyped(target))
if x.isNil() {
@ -669,7 +669,9 @@ func (check *Checker) convertUntypedInternal(x *operand, target Type) {
return
}
// expression value may have been rounded - update if needed
check.updateExprVal(x.expr, x.val)
if update {
check.updateExprVal(x.expr, x.val)
}
} else {
// Non-constant untyped values may appear as the
// result of comparisons (untyped bool), intermediate
@ -694,7 +696,7 @@ func (check *Checker) convertUntypedInternal(x *operand, target Type) {
}
case *Sum:
t.is(func(t Type) bool {
check.convertUntypedInternal(x, t)
check.convertUntypedInternal(x, t, false)
return x.mode != invalid
})
case *Interface:
@ -712,7 +714,9 @@ func (check *Checker) convertUntypedInternal(x *operand, target Type) {
OK:
x.typ = target
check.updateExprType(x.expr, target, true)
if update {
check.updateExprType(x.expr, target, true)
}
return
Error: