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mirror of https://github.com/golang/go synced 2024-11-24 19:00:13 -07:00
go/test/ddd1.go
Matthew Dempsky 581526ce96 cmd/compile: rewrite untyped constant conversion logic
This CL detangles the hairy mess that was convlit+defaultlit. In
particular, it makes the following changes:

1. convlit1 now follows the standard typecheck behavior of setting
"n.Type = nil" if there's an error. Notably, this means for a lot of
test cases, we now avoid reporting useless follow-on error messages.
For example, after reporting that "1 << s + 1.0" has an invalid shift,
we no longer also report that it can't be assigned to string.

2. Previously, assignconvfn had some extra logic for trying to
suppress errors from convlit/defaultlit so that it could provide its
own errors with better context information. Instead, this extra
context information is now passed down into convlit1 directly.

3. Relatedly, this CL also removes redundant calls to defaultlit prior
to assignconv. As a consequence, when an expression doesn't make sense
for a particular assignment (e.g., assigning an untyped string to an
integer), the error messages now say "untyped string" instead of just
"string". This is more consistent with go/types behavior.

4. defaultlit2 is now smarter about only trying to convert pairs of
untyped constants when it's likely to succeed. This allows us to
report better error messages for things like 3+"x"; instead of "cannot
convert 3 to string" we now report "mismatched types untyped number
and untyped string".

Passes toolstash-check.

Change-Id: I26822a02dc35855bd0ac774907b1cf5737e91882
Reviewed-on: https://go-review.googlesource.com/c/go/+/187657
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
2019-09-06 23:15:48 +00:00

65 lines
1.6 KiB
Go

// errorcheck
// Copyright 2010 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.
// Verify that illegal uses of ... are detected.
// Does not compile.
package main
import "unsafe"
func sum(args ...int) int { return 0 }
var (
_ = sum(1, 2, 3)
_ = sum()
_ = sum(1.0, 2.0)
_ = sum(1.5) // ERROR "integer"
_ = sum("hello") // ERROR ".hello. .type untyped string. as type int|incompatible"
_ = sum([]int{1}) // ERROR "\[\]int literal.*as type int|incompatible"
)
func sum3(int, int, int) int { return 0 }
func tuple() (int, int, int) { return 1, 2, 3 }
var (
_ = sum(tuple())
_ = sum(tuple()...) // ERROR "multiple-value"
_ = sum3(tuple())
_ = sum3(tuple()...) // ERROR "multiple-value" "not enough"
)
type T []T
func funny(args ...T) int { return 0 }
var (
_ = funny(nil)
_ = funny(nil, nil)
_ = funny([]T{}) // ok because []T{} is a T; passes []T{[]T{}}
)
func Foo(n int) {}
func bad(args ...int) {
print(1, 2, args...) // ERROR "[.][.][.]"
println(args...) // ERROR "[.][.][.]"
ch := make(chan int)
close(ch...) // ERROR "[.][.][.]"
_ = len(args...) // ERROR "[.][.][.]"
_ = new(int...) // ERROR "[.][.][.]"
n := 10
_ = make([]byte, n...) // ERROR "[.][.][.]"
_ = make([]byte, 10 ...) // ERROR "[.][.][.]"
var x int
_ = unsafe.Pointer(&x...) // ERROR "[.][.][.]"
_ = unsafe.Sizeof(x...) // ERROR "[.][.][.]"
_ = [...]byte("foo") // ERROR "[.][.][.]"
_ = [...][...]int{{1,2,3},{4,5,6}} // ERROR "[.][.][.]"
Foo(x...) // ERROR "invalid use of [.][.][.] in call"
}