img-redundant-alt warning bug (Breaking)

[dogagenc]

Describe the bug
alt attributes with expressions on image elements returns null for static value, but new commit for img-redundant-alt warning checks it as a string.

153b128#diff-8e6b4a7e9c9ba91db066af615305f5f4R491

This breaks whole build process.

Logs
Build log:

[!] (plugin svelte) TypeError: Cannot read property 'match' of null
 src/components/SourcesBar.svelte
 TypeError: Cannot read property 'match' of null
     at Element$1.validate_special_cases (node_modules/svelte/src/compiler/compile/nodes/Element.ts:491:19)
     at Element$1.validate (node_modules/svelte/src/compiler/compile/nodes/Element.ts:275:8)
     at new Element$1 (node_modules/svelte/src/compiler/compile/nodes/Element.ts:220:8)
     ...

To Reproduce
https://svelte.dev/repl/1b24eb90a2bf4b1fbcbc1250b80aecbb?version=3.22.0

Expected behavior
Skip check if alt value is not string or falsy. (null in this case)

Information about your Svelte project:

• Tested on e.x. OS X 10.14, Ubuntu Linux 19.10

• Svelte version: 3.22.0

• Whether your project uses Webpack or Rollup: Rollup

Severity
BREAKING!

Additional context
I'm sending PR soon!

[Conduitry]

Thank you for your quick fix! Released in 3.22.1 - https://svelte.dev/repl/1b24eb90a2bf4b1fbcbc1250b80aecbb?version=3.22.1

[mustafa0x]

Empty alt is also broken — see #4777.