MDS070: same-file-anchor

Every same-file #fragment link must resolve to a heading present in the same file.

A same-file fragment link has a destination beginning with # and no path component — for example [text](#my-heading).

The rule computes GitHub-flavored Markdown heading slugs: lowercase, spaces become -, and non-alphanumeric characters except - are removed. Any fragment that does not match a slug in the file is reported.

This rule is parse-skip-safe: it does not require a goldmark AST. It works on the Layer 0 block-span projection and the shared inline-block parser.

# Config

Enable (default):

rules:
  same-file-anchor: true

Disable:

rules:
  same-file-anchor: false

# Examples

# Bad

# My Heading

See [link](#nonexistent-section).

Reports: same-file anchor #nonexistent-section does not match any heading in this file

# Good

# My Heading

See [link](#my-heading).

## Another Section

See [another link](#another-section).

# See also

• MDS027 — cross-file link and anchor resolution; this rule handles only same-file #fragment links

# Meta-Information

• ID: MDS070
• Name: same-file-anchor
• Status: ready
• Default: enabled
• Fixable: no
• Implementation: source
• Category: link
• markdownlint: MD051 (link-fragments)
• rumdl: MD051 (link-fragments)
• gomarklint: link-fragments