HTML syntax highlighting is incorrect

[Bluebie]

Issue Type: Bug

if you enter in:

<a href=https://example.org/>foo</a> in a html highlighted document, the final / in the href attribute value is highlighted in a grey colour, as if is a self closing xml tag. I believe this behaviour is deceptive, it gives the wrong impression that a html parser would understand the code in this way, but the parsed value of the tag's href attribute is indeed "https://example.org/", which is true in Chromium and in the HTML5 spec.

VS Code version: Code 1.63.2 (Universal) (899d46d, 2021-12-15T09:37:28.172Z)
OS version: Darwin arm64 21.2.0
Restricted Mode: No

System Info

Item	Value
CPUs	Apple M1 (8 x 24)
GPU Status	2d_canvas: enabled gpu_compositing: enabled metal: disabled_off multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on rasterization: enabled skia_renderer: disabled_off_ok video_decode: enabled webgl: enabled webgl2: enabled
Load (avg)	5, 4, 3
Memory (System)	8.00GB (0.11GB free)
Process Argv	--crash-reporter-id 853ff5a3-ca88-48f7-846c-f5ed1cf44a91
Screen Reader	no
VM	0%

Extensions (18)

Extension	Author (truncated)	Version
cddl-languageserver	anw	0.1.3
better-toml	bun	0.3.2
vscode-standardjs-snippets	cap	0.8.15
vscode-standardjs	che	1.4.1
vscode-eslint	dba	2.2.2
vs-code-xml-format	fab	0.1.5
auto-dark-mode	Lin	0.1.7
vscode-docker	ms-	1.18.0
remote-ssh	ms-	0.70.0
remote-ssh-edit	ms-	0.70.0
cpptools	ms-	1.7.1
nodejs-docs	Muk	0.2.2
vscode-hexdump	sle	1.8.1
es6-mocha-snippets	spo	0.2.2
svelte-vscode	sve	105.8.0
vscodeintellicode	Vis	1.2.15
five-server	yan	0.1.2
city-lights-icon-vsc	Yum	1.1.3

(1 theme extensions excluded)

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[gjsjohnmurray]

The attribute value needs to be enclosed in quotes.

[Bluebie]

The attribute value needs to be enclosed in quotes.

No, they don't. Quotes around attribute values that do not contain whitespace or =, >, ", ', ` are redundant when it comes to parsing html documents.

https://html.spec.whatwg.org/multipage/parsing.html#attribute-value-(unquoted)-state

It should not be the responsibility of the syntax highlighter to impose opinion on what constitutes good or bad HTML. That should be the responsibility of linters.

[alexr00]

Thank you for the issue and the spec reference! I have opened an issue in the upstream repository that we get our html syntax highlighting grammar from: textmate/html.tmbundle#118