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[dev.regabi] cmd/compile: fix printing of method expressions

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OTYPE and OMETHEXPR were missing from OpPrec. So add them with the
same precedences as OT{ARRAY,MAP,STRUCT,etc} and
ODOT{,METH,INTER,etc}, respectively. However, ODEREF (which is also
used for pointer types *T) has a lower precedence than other types, so
pointer types need to be specially handled to assign them their
correct, lower precedence.

Incidentally, this also improves the error messages in issue15055.go,
where we were adding unnecessary parentheses around the types in
conversion expressions.

Thanks to Cuong Manh Le for writing the test cases for #43428.

Fixes #43428.

Change-Id: I57e7979babe3ed9ef8a8b5a2a3745e3737dd785f
Reviewed-on: https://go-review.googlesource.com/c/go/+/280873
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com>
This commit is contained in:
Matthew Dempsky 2020-12-30 18:43:10 -08:00
parent 178c667db2
commit 477b049060
3 changed files with 34 additions and 5 deletions
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6
src/cmd/compile/internal/ir/fmt.go
View file

@ -216,6 +216,7 @@ var OpPrec = []int{
OTINTER: 8,
OTMAP: 8,
OTSTRUCT: 8,
OTYPE: 8,
OINDEXMAP: 8,
OINDEX: 8,
OSLICE: 8,
@ -232,6 +233,7 @@ var OpPrec = []int{
ODOT: 8,
OXDOT: 8,
OCALLPART: 8,
OMETHEXPR: 8,
OPLUS: 7,
ONOT: 7,
OBITNOT: 7,
@ -551,8 +553,8 @@ func exprFmt(n Node, s fmt.State, prec int) {
}
nprec := OpPrec[n.Op()]
if n.Op() == OTYPE && n.Sym() != nil {
nprec = 8
if n.Op() == OTYPE && n.Type().IsPtr() {
nprec = OpPrec[ODEREF]
}
if prec > nprec {

8
test/fixedbugs/issue15055.go
View file

@ -8,10 +8,12 @@ package main
func main() {
type name string
_ = []byte("abc", "def", 12) // ERROR "too many arguments to conversion to \[\]byte: \(\[\]byte\)\(.abc., .def., 12\)"
_ = []byte("abc", "def", 12) // ERROR "too many arguments to conversion to \[\]byte: \[\]byte\(.abc., .def., 12\)"
_ = string("a", "b", nil) // ERROR "too many arguments to conversion to string: string\(.a., .b., nil\)"
_ = []byte() // ERROR "missing argument to conversion to \[\]byte: \(\[\]byte\)\(\)"
_ = []byte() // ERROR "missing argument to conversion to \[\]byte: \[\]byte\(\)"
_ = string() // ERROR "missing argument to conversion to string: string\(\)"
_ = *int() // ERROR "missing argument to conversion to int: int\(\)"
_ = (*int)() // ERROR "missing argument to conversion to \*int: \(\*int\)\(\)"
_ = name("a", 1, 3.3) // ERROR "too many arguments to conversion to name: name\(.a., 1, 3.3\)"
_ = map[string]string(nil, nil) // ERROR "too many arguments to conversion to map\[string\]string: \(map\[string\]string\)\(nil, nil\)"
_ = map[string]string(nil, nil) // ERROR "too many arguments to conversion to map\[string\]string: map\[string\]string\(nil, nil\)"
}

25
test/fixedbugs/issue43428.go Normal file
View file

@ -0,0 +1,25 @@
// errorcheck
// 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 p
import "time"
type T int
func (T) Mv() {}
func (*T) Mp() {}
var _ = []int{
T.Mv, // ERROR "cannot use T\.Mv|incompatible type"
(*T).Mv, // ERROR "cannot use \(\*T\)\.Mv|incompatible type"
(*T).Mp, // ERROR "cannot use \(\*T\)\.Mp|incompatible type"
time.Time.GobEncode, // ERROR "cannot use time\.Time\.GobEncode|incompatible type"
(*time.Time).GobEncode, // ERROR "cannot use \(\*time\.Time\)\.GobEncode|incompatible type"
(*time.Time).GobDecode, // ERROR "cannot use \(\*time\.Time\)\.GobDecode|incompatible type"
}