From 8ccc8cb96fbbf70d185155ee0e46f2aef6b624b9 Mon Sep 17 00:00:00 2001
From: Joe Hildebrand <joe-github@cursive.net>
Date: Sat, 11 Jun 2022 10:39:34 -0600
Subject: [PATCH] Ensure Unicode escapes can't be used in character classes yet

---
 lib/parser.js    | 112 +++++++++++++++++++++++++++++++----------------
 src/parser.pegjs |  13 ++++--
 2 files changed, 85 insertions(+), 40 deletions(-)

diff --git a/lib/parser.js b/lib/parser.js
index 62bdb216..d05730a9 100644
--- a/lib/parser.js
+++ b/lib/parser.js
@@ -2145,6 +2145,28 @@ function peg$parse(input, options) {
             peg$currPos = s0;
             s0 = peg$FAILED;
           }
+          if (s0 === peg$FAILED) {
+            s0 = peg$currPos;
+            if (input.charCodeAt(peg$currPos) === 92) {
+              s1 = peg$c29;
+              peg$currPos++;
+            } else {
+              s1 = peg$FAILED;
+              if (peg$silentFails === 0) { peg$fail(peg$e35); }
+            }
+            if (s1 !== peg$FAILED) {
+              s2 = peg$parseExtendedUnicodeEscapeSequence();
+              if (s2 !== peg$FAILED) {
+                s0 = s2;
+              } else {
+                peg$currPos = s0;
+                s0 = peg$FAILED;
+              }
+            } else {
+              peg$currPos = s0;
+              s0 = peg$FAILED;
+            }
+          }
         }
       }
     }
@@ -2395,7 +2417,7 @@ function peg$parse(input, options) {
         if (peg$silentFails === 0) { peg$fail(peg$e35); }
       }
       if (s1 !== peg$FAILED) {
-        s2 = peg$parseEscapeSequence();
+        s2 = peg$parseExtendedEscapeSequence();
         if (s2 !== peg$FAILED) {
           s0 = s2;
         } else {
@@ -2475,7 +2497,7 @@ function peg$parse(input, options) {
         if (peg$silentFails === 0) { peg$fail(peg$e35); }
       }
       if (s1 !== peg$FAILED) {
-        s2 = peg$parseEscapeSequence();
+        s2 = peg$parseExtendedEscapeSequence();
         if (s2 !== peg$FAILED) {
           s0 = s2;
         } else {
@@ -2708,6 +2730,17 @@ function peg$parse(input, options) {
     return s0;
   }
 
+  function peg$parseExtendedEscapeSequence() {
+    var s0;
+
+    s0 = peg$parseEscapeSequence();
+    if (s0 === peg$FAILED) {
+      s0 = peg$parseExtendedUnicodeEscapeSequence();
+    }
+
+    return s0;
+  }
+
   function peg$parseEscapeSequence() {
     var s0, s1, s2, s3;
 
@@ -3060,47 +3093,49 @@ function peg$parse(input, options) {
       peg$currPos = s0;
       s0 = peg$FAILED;
     }
-    if (s0 === peg$FAILED) {
-      s0 = peg$currPos;
-      if (input.substr(peg$currPos, 2) === peg$c48) {
-        s1 = peg$c48;
-        peg$currPos += 2;
+
+    return s0;
+  }
+
+  function peg$parseExtendedUnicodeEscapeSequence() {
+    var s0, s1, s2, s3, s4;
+
+    s0 = peg$currPos;
+    if (input.substr(peg$currPos, 2) === peg$c48) {
+      s1 = peg$c48;
+      peg$currPos += 2;
+    } else {
+      s1 = peg$FAILED;
+      if (peg$silentFails === 0) { peg$fail(peg$e57); }
+    }
+    if (s1 !== peg$FAILED) {
+      s2 = peg$currPos;
+      s3 = [];
+      s4 = peg$parseHexDigit();
+      if (s4 !== peg$FAILED) {
+        while (s4 !== peg$FAILED) {
+          s3.push(s4);
+          s4 = peg$parseHexDigit();
+        }
       } else {
-        s1 = peg$FAILED;
-        if (peg$silentFails === 0) { peg$fail(peg$e57); }
+        s3 = peg$FAILED;
       }
-      if (s1 !== peg$FAILED) {
-        s2 = peg$currPos;
-        s3 = [];
-        s4 = peg$parseHexDigit();
-        if (s4 !== peg$FAILED) {
-          while (s4 !== peg$FAILED) {
-            s3.push(s4);
-            s4 = peg$parseHexDigit();
-          }
+      if (s3 !== peg$FAILED) {
+        s2 = input.substring(s2, peg$currPos);
+      } else {
+        s2 = s3;
+      }
+      if (s2 !== peg$FAILED) {
+        if (input.charCodeAt(peg$currPos) === 125) {
+          s3 = peg$c1;
+          peg$currPos++;
         } else {
           s3 = peg$FAILED;
+          if (peg$silentFails === 0) { peg$fail(peg$e1); }
         }
         if (s3 !== peg$FAILED) {
-          s2 = input.substring(s2, peg$currPos);
-        } else {
-          s2 = s3;
-        }
-        if (s2 !== peg$FAILED) {
-          if (input.charCodeAt(peg$currPos) === 125) {
-            s3 = peg$c1;
-            peg$currPos++;
-          } else {
-            s3 = peg$FAILED;
-            if (peg$silentFails === 0) { peg$fail(peg$e1); }
-          }
-          if (s3 !== peg$FAILED) {
-            peg$savedPos = s0;
-            s0 = peg$f32(s2);
-          } else {
-            peg$currPos = s0;
-            s0 = peg$FAILED;
-          }
+          peg$savedPos = s0;
+          s0 = peg$f32(s2);
         } else {
           peg$currPos = s0;
           s0 = peg$FAILED;
@@ -3109,6 +3144,9 @@ function peg$parse(input, options) {
         peg$currPos = s0;
         s0 = peg$FAILED;
       }
+    } else {
+      peg$currPos = s0;
+      s0 = peg$FAILED;
     }
 
     return s0;
diff --git a/src/parser.pegjs b/src/parser.pegjs
index 88f263cd..5b230960 100644
--- a/src/parser.pegjs
+++ b/src/parser.pegjs
@@ -286,6 +286,7 @@ IdentifierStart
   / "$"
   / "_"
   / "\\" @UnicodeEscapeSequence
+  / "\\" @ExtendedUnicodeEscapeSequence
 
 IdentifierPart
   = IdentifierStart
@@ -329,12 +330,12 @@ StringLiteral "string"
 
 DoubleStringCharacter
   = $(!('"' / "\\" / LineTerminator) SourceCharacter)
-  / "\\" @EscapeSequence
+  / "\\" @ExtendedEscapeSequence
   / LineContinuation
 
 SingleStringCharacter
   = $(!("'" / "\\" / LineTerminator) SourceCharacter)
-  / "\\" @EscapeSequence
+  / "\\" @ExtendedEscapeSequence
   / LineContinuation
 
 CharacterClassMatcher "character class"
@@ -372,6 +373,10 @@ ClassCharacter
 LineContinuation
   = "\\" LineTerminatorSequence { return ""; }
 
+ExtendedEscapeSequence
+  = EscapeSequence
+  / ExtendedUnicodeEscapeSequence
+
 EscapeSequence
   = CharacterEscapeSequence
   / "0" !DecimalDigit { return "\0"; }
@@ -411,7 +416,9 @@ UnicodeEscapeSequence
   = "u" digits:$(HexDigit HexDigit HexDigit HexDigit) {
       return String.fromCharCode(parseInt(digits, 16));
     }
-  / "u{" digits:$HexDigit+ "}" {
+
+ExtendedUnicodeEscapeSequence
+  = "u{" digits:$HexDigit+ "}" {
     // String.fromCodePoint() is not supported in IE11.
     let codepoint = parseInt(digits, 16);
     if (codepoint > 0x10FFFF) {