ThreadSanitizer says:
WARNING: DATA RACE
Write by goroutine 2:
text/template/parse.(*lexer).next()
src/pkg/text/template/parse/lex.go:140 +0x111
text/template/parse.lexInsideAction()
src/pkg/text/template/parse/lex.go:293 +0x144
text/template/parse.(*lexer).run()
src/pkg/text/template/parse/lex.go:223 +0x65
Previous read by goroutine 0:
text/template/parse.(*lexer).lineNumber()
src/pkg/text/template/parse/lex.go:186 +0x50
text/template/parse.(*Tree).action()
src/pkg/text/template/parse/parse.go:317 +0x151
text/template/parse.(*Tree).textOrAction()
src/pkg/text/template/parse/parse.go:288 +0x69
text/template/parse.(*Tree).itemList()
src/pkg/text/template/parse/parse.go:270 +0xbc
text/template/parse.(*Tree).parseControl()
src/pkg/text/template/parse/parse.go:373 +0xfd
text/template/parse.(*Tree).ifControl()
src/pkg/text/template/parse/parse.go:391 +0x3a
text/template/parse.(*Tree).action()
src/pkg/text/template/parse/parse.go:307 +0xed
text/template/parse.(*Tree).textOrAction()
src/pkg/text/template/parse/parse.go:288 +0x69
text/template/parse.(*Tree).parse()
src/pkg/text/template/parse/parse.go:234 +0x408
text/template/parse.(*Tree).Parse()
src/pkg/text/template/parse/parse.go:175 +0x280
text/template/parse.Parse()
src/pkg/text/template/parse/parse.go:37 +0x12d
text/template.(*Template).Parse()
src/pkg/text/template/template.go:168 +0x29c
cmd/go.init()
src/cmd/go/tag_test.go:-1137 +0x190a
main.init()
_testmain.go:20 +0x84
runtime.main()
src/pkg/runtime/proc.c:237 +0x70
Goroutine 2 (running) created at:
text/template/parse.lex()
src/pkg/text/template/parse/lex.go:216 +0x215
text/template/parse.(*Tree).Parse()
src/pkg/text/template/parse/parse.go:174 +0xf4
text/template/parse.Parse()
src/pkg/text/template/parse/parse.go:37 +0x12d
text/template.(*Template).Parse()
src/pkg/text/template/template.go:168 +0x29c
cmd/go.init()
src/cmd/go/tag_test.go:-1137 +0x190a
main.init()
_testmain.go:20 +0x84
runtime.main()
src/pkg/runtime/proc.c:237 +0x70
Similar reports on cmd/go, text/template, text/template/parse, html/template,
net/rpc/jsonrpc.
Total Undefined Behavior under gccgo aside, at least it leads to non-deterministic error
messages, it can contain either the correct line or any arbitrary subsequent line.
