C++: Remove named backreferences

cpp/ql/lib/semmle/code/cpp/regex/internal/ParseRegExp.qll

@@ -337,7 +337,6 @@ abstract class RegExp extends StringLiteral {
   predicate escapedCharacter(int start, int end) {
     this.escapingChar(start) and
     not this.numberedBackreference(start, _, _) and
-    not this.namedBackreference(start, _, _) and
     (
       // hex char \xhh
       this.getChar(start + 1) = "x" and end = start + 4
@@ -648,17 +647,6 @@ abstract class RegExp extends StringLiteral {
     this.isGroupEnd(inEnd)
   }
 
-  /** Matches a named backreference, e.g. `\k<foo>`. */
-  predicate namedBackreference(int start, int end, string name) {
-    this.escapingChar(start) and
-    this.getChar(start + 1) = "k" and
-    this.getChar(start + 2) = "<" and
-    exists(int nameEnd | nameEnd = min(int i | i > start + 3 and this.getChar(i) = ">") |
-      end = nameEnd + 1 and
-      name = this.getText().substring(start + 3, nameEnd)
-    )
-  }
-
   /** Matches a numbered backreference, e.g. `\1`. */
   predicate numberedBackreference(int start, int end, int value) {
     this.escapingChar(start) and
@@ -678,15 +666,13 @@ abstract class RegExp extends StringLiteral {
   /** Whether the text in the range `start,end` is a back reference */
   predicate backreference(int start, int end) {
     this.numberedBackreference(start, end, _)
-    or
-    this.namedBackreference(start, end, _)
   }
 
   /** Gets the number of the back reference in start,end */
   int getBackRefNumber(int start, int end) { this.numberedBackreference(start, end, result) }
 
   /** Gets the name, if it has one, of the back reference in start,end */
-  string getBackRefName(int start, int end) { this.namedBackreference(start, end, result) }
+  string getBackRefName(int start, int end) { none() }
 
   private predicate baseItem(int start, int end) {
     this.characterItem(start, end) and

cpp/ql/test/library-tests/regex/parse.expected

@@ -36,10 +36,6 @@
 
 #-----| [RegExpConstant, RegExpNormalChar] f
 
-#-----| [RegExpConstant, RegExpNormalChar] q
-
-#-----| [RegExpCharacterClassEscape] \s
-
 #-----| [RegExpConstant, RegExpNormalChar] a
 
 #-----| [RegExpConstant, RegExpNormalChar] b
@@ -171,11 +167,6 @@
 #-----| 0 -> [RegExpCharacterClass] [[:alpha:]]
 #-----| 1 -> [RegExpCharacterClass] [[:digit:]]
 
-#-----| [RegExpSequence] (q+)\s+\k<q>+
-#-----| 0 -> [RegExpGroup] (q+)
-#-----| 1 -> [RegExpPlus] \s+
-#-----| 2 -> [RegExpPlus] \k<q>+
-
 #-----| [RegExpSequence] (a+)b+\1
 #-----| 0 -> [RegExpGroup] (a+)
 #-----| 1 -> [RegExpPlus] b+
@@ -235,8 +226,6 @@
 #-----| 2 -> [RegExpOpt] c?
 #-----| 3 -> [RegExpConstant, RegExpNormalChar] d
 
-#-----| [RegExpBackRef] \k<q>
-
 #-----| [RegExpBackRef] \1
 
 #-----| [RegExpSpecialChar] \b
@@ -247,9 +236,6 @@
 
 #-----| [RegExpDot] .
 
-#-----| [RegExpGroup] (q+)
-#-----| 0 -> [RegExpPlus] q+
-
 #-----| [RegExpGroup] (a+)
 #-----| 0 -> [RegExpPlus] a+
 
@@ -353,15 +339,6 @@
 #-----| 0 -> [RegExpConstant, RegExpNormalChar] foo
 #-----| 1 -> [RegExpConstant, RegExpNormalChar] bar
 
-#-----| [RegExpPlus] q+
-#-----| 0 -> [RegExpConstant, RegExpNormalChar] q
-
-#-----| [RegExpPlus] \s+
-#-----| 0 -> [RegExpCharacterClassEscape] \s
-
-#-----| [RegExpPlus] \k<q>+
-#-----| 0 -> [RegExpBackRef] \k<q>
-
 #-----| [RegExpPlus] a+
 #-----| 0 -> [RegExpConstant, RegExpNormalChar] a
 

cpp/ql/test/library-tests/regex/regexp.cpp

@@ -60,7 +60,6 @@ std::regex r_grp4("(?::+)\\w"); // Non-capturing group matching colons
 
 // Backreferences
 std::regex r_bref1("(a+)b+\\1");
-std::regex r_bref2("(q+)\\s+\\k<q>+");
 
 // Two separate character classes, each containing a single POSIX bracket expression
 std::regex r_posix1("[[:alpha:]][[:digit:]]");

cpp/ql/test/library-tests/regex/regexp.expected

@@ -4,7 +4,6 @@ groupNumber
 | file://:0:0:0:0 | (a\|b\|cd) | 1 |
 | file://:0:0:0:0 | (foo) | 1 |
 | file://:0:0:0:0 | (o\|b) | 1 |
-| file://:0:0:0:0 | (q+) | 1 |
 term
 | file://:0:0:0:0 | 0 | RegExpConstant,RegExpNormalChar |
 | file://:0:0:0:0 | 0-9 | RegExpCharacterRange |
@@ -23,8 +22,6 @@ term
 | file://:0:0:0:0 | (foo)* | RegExpStar |
 | file://:0:0:0:0 | (foo)*bar | RegExpSequence |
 | file://:0:0:0:0 | (o\|b) | RegExpGroup |
-| file://:0:0:0:0 | (q+) | RegExpGroup |
-| file://:0:0:0:0 | (q+)\\s+\\k<q>+ | RegExpSequence |
 | file://:0:0:0:0 | - | RegExpConstant,RegExpNormalChar |
 | file://:0:0:0:0 | . | RegExpDot |
 | file://:0:0:0:0 | . | RegExpDot |
@@ -72,15 +69,11 @@ term
 | file://:0:0:0:0 | \\b!a\\B | RegExpSequence |
 | file://:0:0:0:0 | \\d | RegExpCharacterClassEscape |
 | file://:0:0:0:0 | \\d\\D | RegExpSequence |
-| file://:0:0:0:0 | \\k<q> | RegExpBackRef |
-| file://:0:0:0:0 | \\k<q>+ | RegExpPlus |
 | file://:0:0:0:0 | \\n | RegExpConstant,RegExpEscape |
 | file://:0:0:0:0 | \\n | RegExpConstant,RegExpEscape |
 | file://:0:0:0:0 | \\n\\r\\t | RegExpSequence |
 | file://:0:0:0:0 | \\r | RegExpConstant,RegExpEscape |
 | file://:0:0:0:0 | \\s | RegExpCharacterClassEscape |
-| file://:0:0:0:0 | \\s | RegExpCharacterClassEscape |
-| file://:0:0:0:0 | \\s+ | RegExpPlus |
 | file://:0:0:0:0 | \\s\\S | RegExpSequence |
 | file://:0:0:0:0 | \\t | RegExpConstant,RegExpEscape |
 | file://:0:0:0:0 | \\u{987 | RegExpConstant,RegExpEscape |
@@ -156,8 +149,6 @@ term
 | file://:0:0:0:0 | foo\|bar | RegExpAlt |
 | file://:0:0:0:0 | o | RegExpConstant,RegExpNormalChar |
 | file://:0:0:0:0 | o\|b | RegExpAlt |
-| file://:0:0:0:0 | q | RegExpConstant,RegExpNormalChar |
-| file://:0:0:0:0 | q+ | RegExpPlus |
 regExpNormalCharValue
 | file://:0:0:0:0 | 0 | 0 |
 | file://:0:0:0:0 | 1 | 1 |
@@ -185,7 +176,6 @@ regExpNormalCharValue
 | file://:0:0:0:0 | \\n | \n |
 | file://:0:0:0:0 | \\r | \r |
 | file://:0:0:0:0 | \\s | s |
-| file://:0:0:0:0 | \\s | s |
 | file://:0:0:0:0 | \\t | \t |
 | file://:0:0:0:0 | \\u{987 | \u0987 |
 | file://:0:0:0:0 | \\w | w |
@@ -240,4 +230,3 @@ regExpNormalCharValue
 | file://:0:0:0:0 | foo | foo |
 | file://:0:0:0:0 | foo | foo |
 | file://:0:0:0:0 | o | o |
-| file://:0:0:0:0 | q | q |