fmt: Incorrect Hexadecimal Output for Custom Type Alias of uint8 Using fmt.Printf with %x

[t5w0rd]

Go version

go version go1.23.2 darwin/arm64

Output of go env in your module/workspace:

GO111MODULE=''
GOARCH='arm64'
GOBIN=''
GOCACHE='/Users/t5w0rd/Library/Caches/go-build'
GOENV='/Users/t5w0rd/Library/Application Support/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFLAGS=''
GOHOSTARCH='arm64'
GOHOSTOS='darwin'
GOINSECURE=''
GOMODCACHE='/Users/t5w0rd/go/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='darwin'
GOPATH='/Users/t5w0rd/go'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/opt/homebrew/Cellar/go/1.23.2/libexec'
GOSUMDB='sum.golang.org'
GOTMPDIR=''
GOTOOLCHAIN='local'
GOTOOLDIR='/opt/homebrew/Cellar/go/1.23.2/libexec/pkg/tool/darwin_arm64'
GOVCS=''
GOVERSION='go1.23.2'
GODEBUG=''
GOTELEMETRY='local'
GOTELEMETRYDIR='/Users/t5w0rd/Library/Application Support/go/telemetry'
GCCGO='gccgo'
GOARM64='v8.0'
AR='ar'
CC='cc'
CXX='c++'
CGO_ENABLED='1'
GOMOD='/Users/t5w0rd/proj/xmlschema/go.mod'
GOWORK=''
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
PKG_CONFIG='pkg-config'
GOGCCFLAGS='-fPIC -arch arm64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -ffile-prefix-map=/var/folders/w9/ht8w67w93zz6p0p_3_rs3hg40000gn/T/go-build487759924=/tmp/go-build -gno-record-gcc-switches -fno-common'

What did you do?

package main

import (
	"fmt"
	"proto" // Assume this is a valid import path
)

// type NodeProperty uint8  // defined in "proto"

type LocalNodeProperty uint8

func main() {
	var pr proto.NodeProperty
	fmt.Printf("0x%x, %d\n", pr, pr)

	var pr2 LocalNodeProperty
	fmt.Printf("0x%x, %d\n", pr2, pr2)

	fmt.Println("exit")
}

What did you see happen?

0x7330, 0
0x0, 0
exit

What did you expect to see?

0x0, 0
0x0, 0
exit

[gabyhelp]

Related Issues and Documentation

• affected/package: #55102 (closed)
• import/path: issue title #69161 (closed)
• affected/package: unknown #50565 (closed)
• cmd/compile: inconsistent conversion from `float64` to `uint64`(aarch64) #65127 (closed)
• go/types, types2: wrong result of float add float #48315 (closed)
• cmd/go2go: panic with an embedded type param #43759

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}

[seankhliao]

what is proto.NodeProperty

[t5w0rd]

what is proto.NodeProperty

// in proto/xxx.go
package proto

type NodeProperty uint8

[seankhliao]

That doesn't reproduce, you most likely have different issues: https://go.dev/play/p/dbiB5MucBk6

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