4.2: a link target's backtick escapes where it would open a code span inside a directive's content

corpus/round-trip/combinations/directive-link-backticks.json

@@ -0,0 +1,83 @@
+{
+  "content": [
+    {
+      "content": [
+        {
+          "marks": [
+            {
+              "attrs": {
+                "color": ""
+              },
+              "type": "textColor"
+            },
+            {
+              "attrs": {
+                "href": "`"
+              },
+              "type": "link"
+            }
+          ],
+          "text": " ",
+          "type": "text"
+        },
+        {
+          "text": "`a",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "marks": [
+            {
+              "type": "underline"
+            },
+            {
+              "attrs": {
+                "href": "c",
+                "title": "`"
+              },
+              "type": "link"
+            }
+          ],
+          "text": "b",
+          "type": "text"
+        },
+        {
+          "marks": [
+            {
+              "type": "code"
+            }
+          ],
+          "text": "c",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    },
+    {
+      "content": [
+        {
+          "marks": [
+            {
+              "type": "underline"
+            },
+            {
+              "attrs": {
+                "href": "e`f"
+              },
+              "type": "link"
+            }
+          ],
+          "text": "d",
+          "type": "text"
+        }
+      ],
+      "type": "paragraph"
+    }
+  ],
+  "type": "doc",
+  "version": 1
+}

corpus/round-trip/combinations/directive-link-backticks.md

@@ -0,0 +1,5 @@
+:textColor[[ ](\`)]{color=""}`a
+
+:underline[[b](c "\`")]`c`
+
+:underline[[d](e`f)]

spec/flavour.md

@@ -132,9 +132,9 @@ each a named error naming the spelling to write instead.
 **Escaping**: the emitter backslash-escapes whatever literal text would otherwise parse as
 directive syntax — the leading `:` of a would-be directive, `]` inside content, a bracket a link's
 destination and title inside content leave unbalanced (an autolink holding one takes the
-`[text](url)` form), a `{` right after a directive's closing `]`, which would otherwise be read as
+`[text](url)` form) and a backtick there that would open a code span, a `{` right after a
-the attributes it has none of; outside code spans and code blocks, a backslash before `:` in input
+directive's closing `]`, which would otherwise be read as the attributes it has none of; outside
-yields a literal colon.
+code spans and code blocks, a backslash before `:` in input yields a literal colon.
 
 **Malformed directives are error results**, named: an unclosed container at end of input, a body
 fence line of the container's length or longer, a bare colon-run line outside any container or

src/markdown/emit/inline-line.ts

@@ -1,6 +1,6 @@
 import type { AdfMark, AdfNode } from '../../adf/document.ts'
 import type { InlineDirective } from '../../adf/inline-directives.ts'
-import { assembleInlineLine, type InlineEscaping, type InlineSegment, type LineContainer, type NodeRange } from './line-escaping.ts'
+import { assembleInlineLine, isSyntax, type InlineEscaping, type InlineSegment, type LineContainer, type NodeRange } from './line-escaping.ts'
 import { carriedInline } from '../opaque-carry.ts'
 import { claimsLine, holdsNullCharacter, isAutolink } from '../commonmark-grammar.ts'
 import { escapeUnbalanced, spellDestination, spellLinkTarget } from '../link-syntax.ts'
@@ -41,7 +41,7 @@ export function emitInlineLine(nodes: readonly AdfNode[], container: LineContain
 export function tryPipeCell(nodes: readonly AdfNode[], path: ConvertErrorPath): string | undefined {
   const emitted = emitLine(nodes, 'table-cell', path)
   if (!emitted.ok) return undefined
-  if (emitted.value.segments.some((segment) => segment.escaping === 'none' && segment.text.includes('|'))) return undefined
+  if (emitted.value.segments.some((segment) => isSyntax(segment.escaping) && segment.text.includes('|'))) return undefined
   return emitted.value.line
 }
 
@@ -291,7 +291,7 @@ function emitLink(nodes: readonly AdfNode[], mark: AdfMark, depth: number, range
   const inner = emitRun(nodes, depth + 1, range.first, { ...context, bracketed: true })
   if (!inner.ok) return inner
   if (inner.value.carry !== undefined) return inner
-  const spelledTarget = context.bracketed ? escapeUnbalanced(target.value, '[', ']') : target.value
+  const spelledTarget: InlineSegment = context.bracketed ? { escaping: 'bracketed-link-target', text: escapeUnbalanced(target.value, '[', ']') } : syntax(target.value)
-  return success({ segments: [syntax('['), ...inner.value.segments, syntax(`](${spelledTarget})`)] })
+  return success({ segments: [syntax('['), ...inner.value.segments, syntax(']('), spelledTarget, syntax(')')] })
 }
 

src/markdown/emit/line-escaping.ts

@@ -7,7 +7,7 @@ import { readEntityReference } from '../entity-references.ts'
 
 export type EmphasisRole = 'close' | 'open'
 
-export type InlineEscaping = 'backslash' | 'bracketed' | 'none'
+export type InlineEscaping = 'backslash' | 'bracketed' | 'bracketed-link-target' | 'none'
 
 export type NodeRange = { first: number; last: number }
 
@@ -77,10 +77,11 @@ function escape(segments: readonly InlineSegment[], container: LineContainer): A
     const escaping = escapings[index]
     const escapable = escaping === 'backslash' || escaping === 'bracketed'
     if (
-      escapable &&
+      (escapable &&
-      (claimsLineStart(line, index, container) ||
+        (claimsLineStart(line, index, container) ||
-        mergesWithSyntax(scan, escapings, index) ||
+          mergesWithSyntax(scan, escapings, index) ||
-        opensConstruct(scan, linkClose, index, escaping === 'bracketed', container, escaped))
+          opensConstruct(scan, linkClose, index, escaping === 'bracketed', container, escaped))) ||
+      (escaping === 'bracketed-link-target' && scan.charAt(index) === '`' && opensCodeSpan(scan, index, escaped))
     ) {
       output += '\\'
       escaped.add(index)
@@ -181,8 +182,8 @@ function touchesSyntax(scan: string, escapings: readonly (InlineEscaping | undef
   return scan.charAt(cursor) === character && isSyntax(escapings[cursor])
 }
 
-function isSyntax(escaping: InlineEscaping | undefined): boolean {
+export function isSyntax(escaping: InlineEscaping | undefined): boolean {
-  return escaping === 'none'
+  return escaping === 'none' || escaping === 'bracketed-link-target'
 }
 
 function opensConstruct(