diff --git a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/AccessPathSyntax.qll b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/AccessPathSyntax.qll
index 0c3dc8427b2b..f56d52ca7cc0 100644
--- a/csharp/ql/lib/semmle/code/csharp/dataflow/internal/AccessPathSyntax.qll
+++ b/csharp/ql/lib/semmle/code/csharp/dataflow/internal/AccessPathSyntax.qll
@@ -4,6 +4,12 @@
  *
  * This file is used by the shared data flow library and by the JavaScript libraries
  * (which does not use the shared data flow libraries).
+ *
+ * An access path consists of a `.`-separated list of components, which each consist
+ * of an identifier optionally followed by a `[]`-enclosed argument.
+ *
+ * The argument can be be enclosed in single quotes. In this case, any character is allowed in-between
+ * the single quotes, and two consecutive single quotes will be interpreted as an individual single quote.
  */
 
 /**
@@ -116,7 +122,7 @@ private string getRawToken(AccessPath path, int n) {
   // Avoid splitting by '.' since tokens may contain dots, e.g. `Field[foo.Bar.x]`.
   // Instead use regexpFind to match valid tokens, and supplement with a final length
   // check (in `AccessPath.hasSyntaxError`) to ensure all characters were included in a token.
-  result = path.regexpFind("\\w+(?:\\[[^\\]]*\\])?(?=\\.|$)", n, _)
+  result = path.regexpFind("\\w+(?:\\[(?:[^'\\]]*|'(?:[^']|'')*')\\])?(?=\\.|$)", n, _)
 }
 
 /**
@@ -152,7 +158,7 @@ class AccessPathToken extends string {
   AccessPathToken() { this = getRawToken(_, _) }
 
   private string getPart(int part) {
-    result = this.regexpCapture("([^\\[]+)(?:\\[([^\\]]*)\\])?", part)
+    result = this.regexpCapture("([^\\[]+)(?:\\[(?:([^'\\]]*)|'((?:[^']|'')*)')\\])?", part)
   }
 
   /** Gets the name of the token, such as `Member` from `Member[x]` */
@@ -162,10 +168,20 @@ class AccessPathToken extends string {
    * Gets the argument list, such as `1,2` from `Member[1,2]`,
    * or has no result if there are no arguments.
    */
-  string getArgumentList() { result = this.getPart(2) }
+  string getArgumentList() {
+    result = this.getPart(2) or result = this.getPart(3).regexpReplaceAll("''", "'")
+  }
 
-  /** Gets the `n`th argument to this token, such as `x` or `y` from `Member[x,y]`. */
-  string getArgument(int n) { result = this.getArgumentList().splitAt(",", n).trim() }
+  /**
+   * Gets the `n`th argument to this token, such as `x` or `y` from `Member[x,y]`, or
+   * `foo,bar` from `Member['foo,bar']`.
+   */
+  pragma[nomagic]
+  string getArgument(int n) {
+    result = this.getPart(2).splitAt(",", n).trim()
+    or
+    result = this.getPart(3).replaceAll("''", "'") and n = 0
+  }
 
   /** Gets the `n`th argument to this `name` token, such as `x` or `y` from `Member[x,y]`. */
   pragma[nomagic]
diff --git a/go/ql/lib/semmle/go/dataflow/internal/AccessPathSyntax.qll b/go/ql/lib/semmle/go/dataflow/internal/AccessPathSyntax.qll
index 0c3dc8427b2b..f56d52ca7cc0 100644
--- a/go/ql/lib/semmle/go/dataflow/internal/AccessPathSyntax.qll
+++ b/go/ql/lib/semmle/go/dataflow/internal/AccessPathSyntax.qll
@@ -4,6 +4,12 @@
  *
  * This file is used by the shared data flow library and by the JavaScript libraries
  * (which does not use the shared data flow libraries).
+ *
+ * An access path consists of a `.`-separated list of components, which each consist
+ * of an identifier optionally followed by a `[]`-enclosed argument.
+ *
+ * The argument can be be enclosed in single quotes. In this case, any character is allowed in-between
+ * the single quotes, and two consecutive single quotes will be interpreted as an individual single quote.
  */
 
 /**
@@ -116,7 +122,7 @@ private string getRawToken(AccessPath path, int n) {
   // Avoid splitting by '.' since tokens may contain dots, e.g. `Field[foo.Bar.x]`.
   // Instead use regexpFind to match valid tokens, and supplement with a final length
   // check (in `AccessPath.hasSyntaxError`) to ensure all characters were included in a token.
-  result = path.regexpFind("\\w+(?:\\[[^\\]]*\\])?(?=\\.|$)", n, _)
+  result = path.regexpFind("\\w+(?:\\[(?:[^'\\]]*|'(?:[^']|'')*')\\])?(?=\\.|$)", n, _)
 }
 
 /**
@@ -152,7 +158,7 @@ class AccessPathToken extends string {
   AccessPathToken() { this = getRawToken(_, _) }
 
   private string getPart(int part) {
-    result = this.regexpCapture("([^\\[]+)(?:\\[([^\\]]*)\\])?", part)
+    result = this.regexpCapture("([^\\[]+)(?:\\[(?:([^'\\]]*)|'((?:[^']|'')*)')\\])?", part)
   }
 
   /** Gets the name of the token, such as `Member` from `Member[x]` */
@@ -162,10 +168,20 @@ class AccessPathToken extends string {
    * Gets the argument list, such as `1,2` from `Member[1,2]`,
    * or has no result if there are no arguments.
    */
-  string getArgumentList() { result = this.getPart(2) }
+  string getArgumentList() {
+    result = this.getPart(2) or result = this.getPart(3).regexpReplaceAll("''", "'")
+  }
 
-  /** Gets the `n`th argument to this token, such as `x` or `y` from `Member[x,y]`. */
-  string getArgument(int n) { result = this.getArgumentList().splitAt(",", n).trim() }
+  /**
+   * Gets the `n`th argument to this token, such as `x` or `y` from `Member[x,y]`, or
+   * `foo,bar` from `Member['foo,bar']`.
+   */
+  pragma[nomagic]
+  string getArgument(int n) {
+    result = this.getPart(2).splitAt(",", n).trim()
+    or
+    result = this.getPart(3).replaceAll("''", "'") and n = 0
+  }
 
   /** Gets the `n`th argument to this `name` token, such as `x` or `y` from `Member[x,y]`. */
   pragma[nomagic]
diff --git a/java/ql/lib/semmle/code/java/dataflow/internal/AccessPathSyntax.qll b/java/ql/lib/semmle/code/java/dataflow/internal/AccessPathSyntax.qll
index 0c3dc8427b2b..f56d52ca7cc0 100644
--- a/java/ql/lib/semmle/code/java/dataflow/internal/AccessPathSyntax.qll
+++ b/java/ql/lib/semmle/code/java/dataflow/internal/AccessPathSyntax.qll
@@ -4,6 +4,12 @@
  *
  * This file is used by the shared data flow library and by the JavaScript libraries
  * (which does not use the shared data flow libraries).
+ *
+ * An access path consists of a `.`-separated list of components, which each consist
+ * of an identifier optionally followed by a `[]`-enclosed argument.
+ *
+ * The argument can be be enclosed in single quotes. In this case, any character is allowed in-between
+ * the single quotes, and two consecutive single quotes will be interpreted as an individual single quote.
  */
 
 /**
@@ -116,7 +122,7 @@ private string getRawToken(AccessPath path, int n) {
   // Avoid splitting by '.' since tokens may contain dots, e.g. `Field[foo.Bar.x]`.
   // Instead use regexpFind to match valid tokens, and supplement with a final length
   // check (in `AccessPath.hasSyntaxError`) to ensure all characters were included in a token.
-  result = path.regexpFind("\\w+(?:\\[[^\\]]*\\])?(?=\\.|$)", n, _)
+  result = path.regexpFind("\\w+(?:\\[(?:[^'\\]]*|'(?:[^']|'')*')\\])?(?=\\.|$)", n, _)
 }
 
 /**
@@ -152,7 +158,7 @@ class AccessPathToken extends string {
   AccessPathToken() { this = getRawToken(_, _) }
 
   private string getPart(int part) {
-    result = this.regexpCapture("([^\\[]+)(?:\\[([^\\]]*)\\])?", part)
+    result = this.regexpCapture("([^\\[]+)(?:\\[(?:([^'\\]]*)|'((?:[^']|'')*)')\\])?", part)
   }
 
   /** Gets the name of the token, such as `Member` from `Member[x]` */
@@ -162,10 +168,20 @@ class AccessPathToken extends string {
    * Gets the argument list, such as `1,2` from `Member[1,2]`,
    * or has no result if there are no arguments.
    */
-  string getArgumentList() { result = this.getPart(2) }
+  string getArgumentList() {
+    result = this.getPart(2) or result = this.getPart(3).regexpReplaceAll("''", "'")
+  }
 
-  /** Gets the `n`th argument to this token, such as `x` or `y` from `Member[x,y]`. */
-  string getArgument(int n) { result = this.getArgumentList().splitAt(",", n).trim() }
+  /**
+   * Gets the `n`th argument to this token, such as `x` or `y` from `Member[x,y]`, or
+   * `foo,bar` from `Member['foo,bar']`.
+   */
+  pragma[nomagic]
+  string getArgument(int n) {
+    result = this.getPart(2).splitAt(",", n).trim()
+    or
+    result = this.getPart(3).replaceAll("''", "'") and n = 0
+  }
 
   /** Gets the `n`th argument to this `name` token, such as `x` or `y` from `Member[x,y]`. */
   pragma[nomagic]
diff --git a/javascript/ql/lib/semmle/javascript/frameworks/data/internal/AccessPathSyntax.qll b/javascript/ql/lib/semmle/javascript/frameworks/data/internal/AccessPathSyntax.qll
index 0c3dc8427b2b..f56d52ca7cc0 100644
--- a/javascript/ql/lib/semmle/javascript/frameworks/data/internal/AccessPathSyntax.qll
+++ b/javascript/ql/lib/semmle/javascript/frameworks/data/internal/AccessPathSyntax.qll
@@ -4,6 +4,12 @@
  *
  * This file is used by the shared data flow library and by the JavaScript libraries
  * (which does not use the shared data flow libraries).
+ *
+ * An access path consists of a `.`-separated list of components, which each consist
+ * of an identifier optionally followed by a `[]`-enclosed argument.
+ *
+ * The argument can be be enclosed in single quotes. In this case, any character is allowed in-between
+ * the single quotes, and two consecutive single quotes will be interpreted as an individual single quote.
  */
 
 /**
@@ -116,7 +122,7 @@ private string getRawToken(AccessPath path, int n) {
   // Avoid splitting by '.' since tokens may contain dots, e.g. `Field[foo.Bar.x]`.
   // Instead use regexpFind to match valid tokens, and supplement with a final length
   // check (in `AccessPath.hasSyntaxError`) to ensure all characters were included in a token.
-  result = path.regexpFind("\\w+(?:\\[[^\\]]*\\])?(?=\\.|$)", n, _)
+  result = path.regexpFind("\\w+(?:\\[(?:[^'\\]]*|'(?:[^']|'')*')\\])?(?=\\.|$)", n, _)
 }
 
 /**
@@ -152,7 +158,7 @@ class AccessPathToken extends string {
   AccessPathToken() { this = getRawToken(_, _) }
 
   private string getPart(int part) {
-    result = this.regexpCapture("([^\\[]+)(?:\\[([^\\]]*)\\])?", part)
+    result = this.regexpCapture("([^\\[]+)(?:\\[(?:([^'\\]]*)|'((?:[^']|'')*)')\\])?", part)
   }
 
   /** Gets the name of the token, such as `Member` from `Member[x]` */
@@ -162,10 +168,20 @@ class AccessPathToken extends string {
    * Gets the argument list, such as `1,2` from `Member[1,2]`,
    * or has no result if there are no arguments.
    */
-  string getArgumentList() { result = this.getPart(2) }
+  string getArgumentList() {
+    result = this.getPart(2) or result = this.getPart(3).regexpReplaceAll("''", "'")
+  }
 
-  /** Gets the `n`th argument to this token, such as `x` or `y` from `Member[x,y]`. */
-  string getArgument(int n) { result = this.getArgumentList().splitAt(",", n).trim() }
+  /**
+   * Gets the `n`th argument to this token, such as `x` or `y` from `Member[x,y]`, or
+   * `foo,bar` from `Member['foo,bar']`.
+   */
+  pragma[nomagic]
+  string getArgument(int n) {
+    result = this.getPart(2).splitAt(",", n).trim()
+    or
+    result = this.getPart(3).replaceAll("''", "'") and n = 0
+  }
 
   /** Gets the `n`th argument to this `name` token, such as `x` or `y` from `Member[x,y]`. */
   pragma[nomagic]
diff --git a/python/ql/lib/semmle/python/dataflow/new/internal/AccessPathSyntax.qll b/python/ql/lib/semmle/python/dataflow/new/internal/AccessPathSyntax.qll
index 0c3dc8427b2b..f56d52ca7cc0 100644
--- a/python/ql/lib/semmle/python/dataflow/new/internal/AccessPathSyntax.qll
+++ b/python/ql/lib/semmle/python/dataflow/new/internal/AccessPathSyntax.qll
@@ -4,6 +4,12 @@
  *
  * This file is used by the shared data flow library and by the JavaScript libraries
  * (which does not use the shared data flow libraries).
+ *
+ * An access path consists of a `.`-separated list of components, which each consist
+ * of an identifier optionally followed by a `[]`-enclosed argument.
+ *
+ * The argument can be be enclosed in single quotes. In this case, any character is allowed in-between
+ * the single quotes, and two consecutive single quotes will be interpreted as an individual single quote.
  */
 
 /**
@@ -116,7 +122,7 @@ private string getRawToken(AccessPath path, int n) {
   // Avoid splitting by '.' since tokens may contain dots, e.g. `Field[foo.Bar.x]`.
   // Instead use regexpFind to match valid tokens, and supplement with a final length
   // check (in `AccessPath.hasSyntaxError`) to ensure all characters were included in a token.
-  result = path.regexpFind("\\w+(?:\\[[^\\]]*\\])?(?=\\.|$)", n, _)
+  result = path.regexpFind("\\w+(?:\\[(?:[^'\\]]*|'(?:[^']|'')*')\\])?(?=\\.|$)", n, _)
 }
 
 /**
@@ -152,7 +158,7 @@ class AccessPathToken extends string {
   AccessPathToken() { this = getRawToken(_, _) }
 
   private string getPart(int part) {
-    result = this.regexpCapture("([^\\[]+)(?:\\[([^\\]]*)\\])?", part)
+    result = this.regexpCapture("([^\\[]+)(?:\\[(?:([^'\\]]*)|'((?:[^']|'')*)')\\])?", part)
   }
 
   /** Gets the name of the token, such as `Member` from `Member[x]` */
@@ -162,10 +168,20 @@ class AccessPathToken extends string {
    * Gets the argument list, such as `1,2` from `Member[1,2]`,
    * or has no result if there are no arguments.
    */
-  string getArgumentList() { result = this.getPart(2) }
+  string getArgumentList() {
+    result = this.getPart(2) or result = this.getPart(3).regexpReplaceAll("''", "'")
+  }
 
-  /** Gets the `n`th argument to this token, such as `x` or `y` from `Member[x,y]`. */
-  string getArgument(int n) { result = this.getArgumentList().splitAt(",", n).trim() }
+  /**
+   * Gets the `n`th argument to this token, such as `x` or `y` from `Member[x,y]`, or
+   * `foo,bar` from `Member['foo,bar']`.
+   */
+  pragma[nomagic]
+  string getArgument(int n) {
+    result = this.getPart(2).splitAt(",", n).trim()
+    or
+    result = this.getPart(3).replaceAll("''", "'") and n = 0
+  }
 
   /** Gets the `n`th argument to this `name` token, such as `x` or `y` from `Member[x,y]`. */
   pragma[nomagic]
diff --git a/ruby/ql/lib/codeql/ruby/dataflow/internal/AccessPathSyntax.qll b/ruby/ql/lib/codeql/ruby/dataflow/internal/AccessPathSyntax.qll
index 0c3dc8427b2b..f56d52ca7cc0 100644
--- a/ruby/ql/lib/codeql/ruby/dataflow/internal/AccessPathSyntax.qll
+++ b/ruby/ql/lib/codeql/ruby/dataflow/internal/AccessPathSyntax.qll
@@ -4,6 +4,12 @@
  *
  * This file is used by the shared data flow library and by the JavaScript libraries
  * (which does not use the shared data flow libraries).
+ *
+ * An access path consists of a `.`-separated list of components, which each consist
+ * of an identifier optionally followed by a `[]`-enclosed argument.
+ *
+ * The argument can be be enclosed in single quotes. In this case, any character is allowed in-between
+ * the single quotes, and two consecutive single quotes will be interpreted as an individual single quote.
  */
 
 /**
@@ -116,7 +122,7 @@ private string getRawToken(AccessPath path, int n) {
   // Avoid splitting by '.' since tokens may contain dots, e.g. `Field[foo.Bar.x]`.
   // Instead use regexpFind to match valid tokens, and supplement with a final length
   // check (in `AccessPath.hasSyntaxError`) to ensure all characters were included in a token.
-  result = path.regexpFind("\\w+(?:\\[[^\\]]*\\])?(?=\\.|$)", n, _)
+  result = path.regexpFind("\\w+(?:\\[(?:[^'\\]]*|'(?:[^']|'')*')\\])?(?=\\.|$)", n, _)
 }
 
 /**
@@ -152,7 +158,7 @@ class AccessPathToken extends string {
   AccessPathToken() { this = getRawToken(_, _) }
 
   private string getPart(int part) {
-    result = this.regexpCapture("([^\\[]+)(?:\\[([^\\]]*)\\])?", part)
+    result = this.regexpCapture("([^\\[]+)(?:\\[(?:([^'\\]]*)|'((?:[^']|'')*)')\\])?", part)
   }
 
   /** Gets the name of the token, such as `Member` from `Member[x]` */
@@ -162,10 +168,20 @@ class AccessPathToken extends string {
    * Gets the argument list, such as `1,2` from `Member[1,2]`,
    * or has no result if there are no arguments.
    */
-  string getArgumentList() { result = this.getPart(2) }
+  string getArgumentList() {
+    result = this.getPart(2) or result = this.getPart(3).regexpReplaceAll("''", "'")
+  }
 
-  /** Gets the `n`th argument to this token, such as `x` or `y` from `Member[x,y]`. */
-  string getArgument(int n) { result = this.getArgumentList().splitAt(",", n).trim() }
+  /**
+   * Gets the `n`th argument to this token, such as `x` or `y` from `Member[x,y]`, or
+   * `foo,bar` from `Member['foo,bar']`.
+   */
+  pragma[nomagic]
+  string getArgument(int n) {
+    result = this.getPart(2).splitAt(",", n).trim()
+    or
+    result = this.getPart(3).replaceAll("''", "'") and n = 0
+  }
 
   /** Gets the `n`th argument to this `name` token, such as `x` or `y` from `Member[x,y]`. */
   pragma[nomagic]
diff --git a/ruby/ql/test/library-tests/dataflow/summaries/Summaries.expected b/ruby/ql/test/library-tests/dataflow/summaries/Summaries.expected
index eb990f9ab275..4ca6445f9973 100644
--- a/ruby/ql/test/library-tests/dataflow/summaries/Summaries.expected
+++ b/ruby/ql/test/library-tests/dataflow/summaries/Summaries.expected
@@ -44,6 +44,10 @@ edges
 | summaries.rb:1:1:1:7 | tainted | summaries.rb:147:16:147:22 | tainted |
 | summaries.rb:1:1:1:7 | tainted | summaries.rb:150:39:150:45 | tainted |
 | summaries.rb:1:1:1:7 | tainted | summaries.rb:150:39:150:45 | tainted |
+| summaries.rb:1:1:1:7 | tainted | summaries.rb:154:5:154:11 | tainted |
+| summaries.rb:1:1:1:7 | tainted | summaries.rb:154:5:154:11 | tainted |
+| summaries.rb:1:1:1:7 | tainted | summaries.rb:155:10:155:16 | ... = ... |
+| summaries.rb:1:1:1:7 | tainted | summaries.rb:155:10:155:16 | ... = ... |
 | summaries.rb:1:11:1:36 | call to identity | summaries.rb:1:1:1:7 | tainted |
 | summaries.rb:1:11:1:36 | call to identity | summaries.rb:1:1:1:7 | tainted |
 | summaries.rb:1:20:1:36 | call to source | summaries.rb:1:11:1:36 | call to identity |
@@ -231,6 +235,8 @@ edges
 | summaries.rb:122:16:122:22 | [post] tainted | summaries.rb:145:26:145:32 | tainted |
 | summaries.rb:122:16:122:22 | [post] tainted | summaries.rb:147:16:147:22 | tainted |
 | summaries.rb:122:16:122:22 | [post] tainted | summaries.rb:150:39:150:45 | tainted |
+| summaries.rb:122:16:122:22 | [post] tainted | summaries.rb:154:5:154:11 | tainted |
+| summaries.rb:122:16:122:22 | [post] tainted | summaries.rb:155:10:155:16 | ... = ... |
 | summaries.rb:122:16:122:22 | tainted | summaries.rb:122:16:122:22 | [post] tainted |
 | summaries.rb:122:16:122:22 | tainted | summaries.rb:122:25:122:25 | [post] y |
 | summaries.rb:122:16:122:22 | tainted | summaries.rb:122:33:122:33 | [post] z |
@@ -474,6 +480,10 @@ nodes
 | summaries.rb:147:16:147:22 | tainted | semmle.label | tainted |
 | summaries.rb:150:39:150:45 | tainted | semmle.label | tainted |
 | summaries.rb:150:39:150:45 | tainted | semmle.label | tainted |
+| summaries.rb:154:5:154:11 | tainted | semmle.label | tainted |
+| summaries.rb:154:5:154:11 | tainted | semmle.label | tainted |
+| summaries.rb:155:10:155:16 | ... = ... | semmle.label | ... = ... |
+| summaries.rb:155:10:155:16 | ... = ... | semmle.label | ... = ... |
 subpaths
 invalidSpecComponent
 #select
@@ -573,6 +583,10 @@ invalidSpecComponent
 | summaries.rb:147:16:147:22 | tainted | summaries.rb:1:20:1:36 | call to source | summaries.rb:147:16:147:22 | tainted | $@ | summaries.rb:1:20:1:36 | call to source | call to source |
 | summaries.rb:150:39:150:45 | tainted | summaries.rb:1:20:1:36 | call to source | summaries.rb:150:39:150:45 | tainted | $@ | summaries.rb:1:20:1:36 | call to source | call to source |
 | summaries.rb:150:39:150:45 | tainted | summaries.rb:1:20:1:36 | call to source | summaries.rb:150:39:150:45 | tainted | $@ | summaries.rb:1:20:1:36 | call to source | call to source |
+| summaries.rb:154:5:154:11 | tainted | summaries.rb:1:20:1:36 | call to source | summaries.rb:154:5:154:11 | tainted | $@ | summaries.rb:1:20:1:36 | call to source | call to source |
+| summaries.rb:154:5:154:11 | tainted | summaries.rb:1:20:1:36 | call to source | summaries.rb:154:5:154:11 | tainted | $@ | summaries.rb:1:20:1:36 | call to source | call to source |
+| summaries.rb:155:10:155:16 | ... = ... | summaries.rb:1:20:1:36 | call to source | summaries.rb:155:10:155:16 | ... = ... | $@ | summaries.rb:1:20:1:36 | call to source | call to source |
+| summaries.rb:155:10:155:16 | ... = ... | summaries.rb:1:20:1:36 | call to source | summaries.rb:155:10:155:16 | ... = ... | $@ | summaries.rb:1:20:1:36 | call to source | call to source |
 warning
 | CSV type row should have 3 columns but has 1: TooFewColumns |
 | CSV type row should have 3 columns but has 6: TooManyColumns;;Member[Foo].Instance;too;many;columns |
diff --git a/ruby/ql/test/library-tests/dataflow/summaries/Summaries.ql b/ruby/ql/test/library-tests/dataflow/summaries/Summaries.ql
index b59862d0e5a8..98020e221c3d 100644
--- a/ruby/ql/test/library-tests/dataflow/summaries/Summaries.ql
+++ b/ruby/ql/test/library-tests/dataflow/summaries/Summaries.ql
@@ -145,6 +145,8 @@ private class SinkFromModel extends ModelInput::SinkModelCsv {
         "Foo!;Method[getSinks].ReturnValue.Element[any].Method[mySink].Argument[0];test-sink", //
         "Foo!;Method[arraySink].Argument[0].Element[any];test-sink", //
         "Foo!;Method[secondArrayElementIsSink].Argument[0].Element[1];test-sink", //
+        "Foo!;Method['[]'].Argument[0];test-sink", //
+        "Bar!;Method['[]='].Argument[1];test-sink", //
       ]
   }
 }
diff --git a/ruby/ql/test/library-tests/dataflow/summaries/summaries.rb b/ruby/ql/test/library-tests/dataflow/summaries/summaries.rb
index cff6f00884ee..3ad024ecddce 100644
--- a/ruby/ql/test/library-tests/dataflow/summaries/summaries.rb
+++ b/ruby/ql/test/library-tests/dataflow/summaries/summaries.rb
@@ -150,3 +150,6 @@ def userDefinedFunction(x, y)
 Foo.secondArrayElementIsSink(["safe", tainted, "safe"]) # $ hasValueFlow=tainted
 Foo.secondArrayElementIsSink(["safe", "safe", tainted])
 Foo.secondArrayElementIsSink([tainted] * 10) # $ MISSING: hasValueFlow=tainted
+
+Foo[tainted] # $ hasValueFlow=tainted
+Bar[1] = tainted # $ hasValueFlow=tainted
diff --git a/swift/ql/lib/codeql/swift/dataflow/internal/AccessPathSyntax.qll b/swift/ql/lib/codeql/swift/dataflow/internal/AccessPathSyntax.qll
index 0c3dc8427b2b..f56d52ca7cc0 100644
--- a/swift/ql/lib/codeql/swift/dataflow/internal/AccessPathSyntax.qll
+++ b/swift/ql/lib/codeql/swift/dataflow/internal/AccessPathSyntax.qll
@@ -4,6 +4,12 @@
  *
  * This file is used by the shared data flow library and by the JavaScript libraries
  * (which does not use the shared data flow libraries).
+ *
+ * An access path consists of a `.`-separated list of components, which each consist
+ * of an identifier optionally followed by a `[]`-enclosed argument.
+ *
+ * The argument can be be enclosed in single quotes. In this case, any character is allowed in-between
+ * the single quotes, and two consecutive single quotes will be interpreted as an individual single quote.
  */
 
 /**
@@ -116,7 +122,7 @@ private string getRawToken(AccessPath path, int n) {
   // Avoid splitting by '.' since tokens may contain dots, e.g. `Field[foo.Bar.x]`.
   // Instead use regexpFind to match valid tokens, and supplement with a final length
   // check (in `AccessPath.hasSyntaxError`) to ensure all characters were included in a token.
-  result = path.regexpFind("\\w+(?:\\[[^\\]]*\\])?(?=\\.|$)", n, _)
+  result = path.regexpFind("\\w+(?:\\[(?:[^'\\]]*|'(?:[^']|'')*')\\])?(?=\\.|$)", n, _)
 }
 
 /**
@@ -152,7 +158,7 @@ class AccessPathToken extends string {
   AccessPathToken() { this = getRawToken(_, _) }
 
   private string getPart(int part) {
-    result = this.regexpCapture("([^\\[]+)(?:\\[([^\\]]*)\\])?", part)
+    result = this.regexpCapture("([^\\[]+)(?:\\[(?:([^'\\]]*)|'((?:[^']|'')*)')\\])?", part)
   }
 
   /** Gets the name of the token, such as `Member` from `Member[x]` */
@@ -162,10 +168,20 @@ class AccessPathToken extends string {
    * Gets the argument list, such as `1,2` from `Member[1,2]`,
    * or has no result if there are no arguments.
    */
-  string getArgumentList() { result = this.getPart(2) }
+  string getArgumentList() {
+    result = this.getPart(2) or result = this.getPart(3).regexpReplaceAll("''", "'")
+  }
 
-  /** Gets the `n`th argument to this token, such as `x` or `y` from `Member[x,y]`. */
-  string getArgument(int n) { result = this.getArgumentList().splitAt(",", n).trim() }
+  /**
+   * Gets the `n`th argument to this token, such as `x` or `y` from `Member[x,y]`, or
+   * `foo,bar` from `Member['foo,bar']`.
+   */
+  pragma[nomagic]
+  string getArgument(int n) {
+    result = this.getPart(2).splitAt(",", n).trim()
+    or
+    result = this.getPart(3).replaceAll("''", "'") and n = 0
+  }
 
   /** Gets the `n`th argument to this `name` token, such as `x` or `y` from `Member[x,y]`. */
   pragma[nomagic]