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cmd/compile/internal/types2: use combined type and ordinary args for type inference

Fixes #44799.

Change-Id: I51d5b6d6fdfcf47b87bf40b1f7e31c3284c2813f
Reviewed-on: https://go-review.googlesource.com/c/go/+/308372
Trust: Robert Griesemer <gri@golang.org>
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Robert Findley <rfindley@google.com>
This commit is contained in:
Robert Griesemer 2021-04-07 22:36:15 -07:00
parent a6d95b4508
commit 3f4977bd58
4 changed files with 57 additions and 7 deletions

View File

@ -129,7 +129,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
arg(&x, i)
xlist = append(xlist, &x)
}
check.arguments(call, sig, xlist) // discard result (we know the result type)
check.arguments(call, sig, nil, xlist) // discard result (we know the result type)
// ok to continue even if check.arguments reported errors
x.mode = value

View File

@ -67,9 +67,14 @@ func (check *Checker) funcInst(x *operand, inst *syntax.IndexExpr) {
}
func (check *Checker) callExpr(x *operand, call *syntax.CallExpr) exprKind {
var inst *syntax.IndexExpr // function instantiation, if any
if iexpr, _ := call.Fun.(*syntax.IndexExpr); iexpr != nil {
if check.indexExpr(x, iexpr) {
check.funcInst(x, iexpr)
// Delay function instantiation to argument checking,
// where we combine type and value arguments for type
// inference.
assert(x.mode == value)
inst = iexpr
}
x.expr = iexpr
check.record(x)
@ -137,9 +142,33 @@ func (check *Checker) callExpr(x *operand, call *syntax.CallExpr) exprKind {
return statement
}
// evaluate type arguments, if any
var targs []Type
if inst != nil {
xlist := unpackExpr(inst.Index)
targs = check.typeList(xlist)
if targs == nil {
check.use(call.ArgList...)
x.mode = invalid
x.expr = call
return statement
}
assert(len(targs) == len(xlist))
// check number of type arguments (got) vs number of type parameters (want)
got, want := len(targs), len(sig.tparams)
if got > want {
check.errorf(xlist[want], "got %d type arguments but want %d", got, want)
check.use(call.ArgList...)
x.mode = invalid
x.expr = call
return statement
}
}
// evaluate arguments
args, _ := check.exprList(call.ArgList, false)
sig = check.arguments(call, sig, args)
sig = check.arguments(call, sig, targs, args)
// determine result
switch sig.results.Len() {
@ -208,7 +237,7 @@ func (check *Checker) exprList(elist []syntax.Expr, allowCommaOk bool) (xlist []
return
}
func (check *Checker) arguments(call *syntax.CallExpr, sig *Signature, args []*operand) (rsig *Signature) {
func (check *Checker) arguments(call *syntax.CallExpr, sig *Signature, targs []Type, args []*operand) (rsig *Signature) {
rsig = sig
// TODO(gri) try to eliminate this extra verification loop
@ -292,7 +321,7 @@ func (check *Checker) arguments(call *syntax.CallExpr, sig *Signature, args []*o
if len(sig.tparams) > 0 {
// TODO(gri) provide position information for targs so we can feed
// it to the instantiate call for better error reporting
targs := check.infer(call.Pos(), sig.tparams, nil, sigParams, args, true)
targs = check.infer(call.Pos(), sig.tparams, targs, sigParams, args, true)
if targs == nil {
return // error already reported
}

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@ -1,4 +1,3 @@
// UNREVIEWED
// 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.
@ -17,5 +16,8 @@ func f[V interface{}, A, B Box[V]]() {}
func _() {
f[int, Optional[int], Optional[int]]()
f[int, Optional[int], Optional /* ERROR does not satisfy Box */ [string]]()
_ = f[int, Optional[int], Optional /* ERROR does not satisfy Box */ [string]]
// TODO(gri) Provide better position information here.
// See TODO in call.go, Checker.arguments.
f[int, Optional[int], Optional[string]]( /* ERROR does not satisfy Box */ )
}

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@ -0,0 +1,19 @@
// Copyright 2021 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 main
func Map[F, T any](s []F, f func(F) T) []T { return nil }
func Reduce[Elem1, Elem2 any](s []Elem1, initializer Elem2, f func(Elem2, Elem1) Elem2) Elem2 { var x Elem2; return x }
func main() {
var s []int
var f1 func(int) float64
var f2 func(float64, int) float64
_ = Map[int](s, f1)
_ = Map(s, f1)
_ = Reduce[int](s, 0, f2)
_ = Reduce(s, 0, f2)
}