text/template: A terminator is erroneously detected in a field that starts with the same character as the right delimiter

[mprahl]

What version of Go are you using (go version)?

$ go version                                          
go version go1.18 linux/amd64

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/home/mprahl/.cache/go-build"
GOENV="/home/mprahl/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/home/mprahl/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/home/mprahl/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/local/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.18"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="gcc"
CXX="g++"
CGO_ENABLED="1"
GOMOD="/home/mprahl/git/go/src/go.mod"
GOWORK=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build4256537278=/tmp/go-build -gno-record-gcc-switches"

What did you do?

package main

import (
	"os"
	"text/template"
)

func main() {
	tmpl, err := template.New("test").Delims("{{hub", "hub}}").Parse(`{{hub .Object.host hub}}`)
	if err != nil {
		panic(err)
	}

	err = tmpl.Execute(os.Stdout, struct{ Object map[string]string }{map[string]string{"host": "value"}})
	if err != nil {
		panic(err)
	}
}

What did you expect to see?

go run test.go
value

What did you see instead?

go run test.go
panic: template: test:1: unexpected <.> in operand

goroutine 1 [running]:
main.main()
        /tmp/test.go:11 +0x2ba
exit status 2

[gopherbot]

Change https://go.dev/cl/398475 mentions this issue: text/template: Fix terminator detection in fields