Rust: simplify synth constructors

Author: aibaars

rust/ql/.generated.list

@@ -12,11 +12,7 @@ private import codeql.rust.elements.internal.FormatConstructor
  *  The characteristic predicate of `FormatArgument` synthesized instances.
  *  INTERNAL: Do not use.
  */
-predicate constructFormatArgument(Raw::FormatArgsExpr parent, int index, int kind) {
-  formatArgument(parent, index, kind, _, _, _)
-}
-
-predicate formatArgument(
+predicate constructFormatArgument(
   Raw::FormatArgsExpr parent, int index, int kind, string value, boolean positional, int offset
 ) {
   exists(string text, int formatOffset, int group |

rust/ql/lib/codeql/rust/elements/internal/FormatArgumentConstructor.qll

@@ -32,10 +32,7 @@ module Impl {
     string name;
     private int offset;
 
-    FormatArgument() {
-      this = Synth::TFormatArgument(parent, index, kind) and
-      formatArgument(parent, index, kind, name, _, offset)
-    }
+    FormatArgument() { this = Synth::TFormatArgument(parent, index, kind, name, _, offset) }
 
     override string toString() { result = name }
 
@@ -53,7 +50,7 @@ module Impl {
       endcolumn = startcolumn + name.length() - 1
     }
 
-    override Format getParent() { result = Synth::TFormat(parent, index) }
+    override Format getParent() { result = Synth::TFormat(parent, index, _, _) }
   }
 
   /**
@@ -64,7 +61,7 @@ module Impl {
    * ```
    */
   class PositionalFormatArgument extends FormatArgument {
-    PositionalFormatArgument() { formatArgument(parent, index, kind, _, true, _) }
+    PositionalFormatArgument() { this = Synth::TFormatArgument(_, _, _, _, true, _) }
 
     /** Gets the index of this positional argument */
     int getIndex() { result = name.toInt() }
@@ -78,7 +75,7 @@ module Impl {
    * ```
    */
   class NamedFormatArgument extends FormatArgument {
-    NamedFormatArgument() { formatArgument(parent, index, kind, _, false, _) }
+    NamedFormatArgument() { this = Synth::TFormatArgument(_, _, _, _, false, _) }
 
     /** Gets the name of this named argument */
     string getName() { result = name }

rust/ql/lib/codeql/rust/elements/internal/FormatArgumentImpl.qll

@@ -9,9 +9,13 @@ private import codeql.rust.elements.internal.generated.Raw
 /**
  *  The characteristic predicate of `Format` synthesized instances.
  *  INTERNAL: Do not use.
+ *
+ * Match an element of a format string, either text (`Hello`) or a format placeholder (`{}`).
  */
-predicate constructFormat(Raw::FormatArgsExpr parent, int index) {
-  formatElement(parent, index, _).regexpMatch(formatRegex())
+predicate constructFormat(Raw::FormatArgsExpr parent, int index, string text, int offset) {
+  text = formatElement(parent, index, offset) and
+  text.charAt(0) = "{" and
+  text.charAt(1) != "{"
 }
 
 /**
@@ -28,9 +32,11 @@ string formatElement(Raw::FormatArgsExpr parent, int occurrenceIndex, int occurr
 }
 
 /**
- * A regular expression for matching format elements in a formatting template. The
+ * A regular expression for matching format elements in a formatting template. The syntax of
+ * formatting templates is defined at https://doc.rust-lang.org/stable/std/fmt/#syntax . The
  * regular expression is generated from the following python code:
  *
+ *
  * ```python
  * identifier = "([A-Za-z_][A-Za-z0-9_]*)"
  * integer = "([0-9]+)"

rust/ql/lib/codeql/rust/elements/internal/FormatConstructor.qll

@@ -28,9 +28,7 @@ module Impl {
     private int index;
     private int offset;
 
-    Format() {
-      this = Synth::TFormat(parent, index) and text = formatElement(parent, index, offset)
-    }
+    Format() { this = Synth::TFormat(parent, index, text, offset) }
 
     override string toString() { result = text }
 
@@ -58,7 +56,7 @@ module Impl {
      * ```
      */
     FormatArgument getArgumentRef() {
-      result.getParent() = this and result = Synth::TFormatArgument(_, _, 0)
+      result.getParent() = this and result = Synth::TFormatArgument(_, _, 0, _, _, _)
     }
 
     /**
@@ -70,7 +68,7 @@ module Impl {
      * ```
      */
     FormatArgument getWidthArgument() {
-      result.getParent() = this and result = Synth::TFormatArgument(_, _, 1)
+      result.getParent() = this and result = Synth::TFormatArgument(_, _, 1, _, _, _)
     }
 
     /**
@@ -82,7 +80,7 @@ module Impl {
      * ```
      */
     FormatArgument getPrecisionArgument() {
-      result.getParent() = this and result = Synth::TFormatArgument(_, _, 2)
+      result.getParent() = this and result = Synth::TFormatArgument(_, _, 2, _, _, _)
     }
   }
 }

rust/ql/lib/codeql/rust/elements/internal/FormatImpl.qll

@@ -1763,7 +1763,7 @@ class FormatTemplateVariableAccess(Expr):
 
 
 @qltest.skip
-@synth.on_arguments(parent=FormatArgsExpr, index=int)
+@synth.on_arguments(parent=FormatArgsExpr, index=int, text=string, offset=int)
 class Format(Locatable):
     """
     A format element in a formatting template. For example the `{}` in:
@@ -1776,7 +1776,7 @@ class Format(Locatable):
 
 
 @qltest.skip
-@synth.on_arguments(parent=FormatArgsExpr, index=int, kind=int)
+@synth.on_arguments(parent=FormatArgsExpr, index=int, kind=int, name=string, positional=boolean, offset=int)
 class FormatArgument(Locatable):
     """
     An argument in a format element in a formatting template. For example the `width`, `precision`, and `value` in: