C++: Fix PR feedback

Note that the various predicates to access the singleton instances of the `EdgeKind` classes have been moved into a module named `EdgeKind`.

cpp/ql/src/semmle/code/cpp/ir/implementation/EdgeKind.qll

@@ -29,12 +29,6 @@ class GotoEdge extends EdgeKind, TGotoEdge {
   final override string toString() { result = "Goto" }
 }
 
-/**
- * Gets the single instance of `GotoEdge`, representing the unconditional successor of an
- * `Instruction`
- */
-GotoEdge gotoEdge() { result = TGotoEdge() }
-
 /**
  * A "true" edge, representing the successor of a conditional branch when the
  * condition is non-zero.
@@ -43,12 +37,6 @@ class TrueEdge extends EdgeKind, TTrueEdge {
   final override string toString() { result = "True" }
 }
 
-/**
- * Gets the single instance of `TrueEdge`, representing the successor of a conditional branch when
- * the condition is non-zero.
- */
-TrueEdge trueEdge() { result = TTrueEdge() }
-
 /**
  * A "false" edge, representing the successor of a conditional branch when the
  * condition is zero.
@@ -57,12 +45,6 @@ class FalseEdge extends EdgeKind, TFalseEdge {
   final override string toString() { result = "False" }
 }
 
-/**
- * Gets the single instance of `FalseEdge`, representing the successor of a conditional branch when
- * the condition is zero.
- */
-FalseEdge falseEdge() { result = TFalseEdge() }
-
 /**
  * An "exception" edge, representing the successor of an instruction when that
  * instruction's evaluation throws an exception.
@@ -71,12 +53,6 @@ class ExceptionEdge extends EdgeKind, TExceptionEdge {
   final override string toString() { result = "Exception" }
 }
 
-/**
- * Gets the single instance of `ExceptionEdge`, representing the successor of an instruction when
- * that instruction's evaluation throws an exception.
- */
-ExceptionEdge exceptionEdge() { result = TExceptionEdge() }
-
 /**
  * A "default" edge, representing the successor of a `Switch` instruction when
  * none of the case values matches the condition value.
@@ -85,12 +61,6 @@ class DefaultEdge extends EdgeKind, TDefaultEdge {
   final override string toString() { result = "Default" }
 }
 
-/**
- * Gets the single instance of `DefaultEdge`, representing the successor of a `Switch` instruction
- * when none of the case values matches the condition value.
- */
-DefaultEdge defaultEdge() { result = TDefaultEdge() }
-
 /**
  * A "case" edge, representing the successor of a `Switch` instruction when the
  * the condition value matches a correponding `case` label.
@@ -112,8 +82,45 @@ class CaseEdge extends EdgeKind, TCaseEdge {
   string getMaxValue() { result = maxValue }
 }
 
-/**
- * Gets the `CaseEdge` representing the successor of a `Switch` instruction corresponding to the
- * `case` label with the specified lower and upper bounds.
- */
-CaseEdge caseEdge(string minValue, string maxValue) { result = TCaseEdge(minValue, maxValue) }
+module EdgeKind {
+  /**
+   * Gets the single instance of the `GotoEdge` class.
+   */
+  GotoEdge gotoEdge() { result = TGotoEdge() }
+
+  /**
+   * Gets the single instance of the `TrueEdge` class.
+   */
+  TrueEdge trueEdge() { result = TTrueEdge() }
+
+  /**
+   * Gets the single instance of the `FalseEdge` class.
+   */
+  FalseEdge falseEdge() { result = TFalseEdge() }
+
+  /**
+   * Gets the single instance of the `ExceptionEdge` class.
+   */
+  ExceptionEdge exceptionEdge() { result = TExceptionEdge() }
+
+  /**
+   * Gets the single instance of the `DefaultEdge` class.
+   */
+  DefaultEdge defaultEdge() { result = TDefaultEdge() }
+
+  /**
+   * Gets the `CaseEdge` representing a `case` label with the specified lower and upper bounds.
+   * For example:
+   * ```
+   * switch (x) {
+   *   case 1:  // Edge kind is `caseEdge("1", "1")`
+   *     return x;
+   *   case 2...8:  // Edge kind is `caseEdge("2", "8")`
+   *     return x - 1;
+   *   default:  // Edge kind is `defaultEdge()`
+   *     return 0;
+   *  }
+   * ```
+   */
+  CaseEdge caseEdge(string minValue, string maxValue) { result = TCaseEdge(minValue, maxValue) }
+}

cpp/ql/src/semmle/code/cpp/ir/implementation/TempVariableTag.qll

@@ -6,8 +6,8 @@ private import internal.TempVariableTagInternal
 private import Imports::TempVariableTag
 
 /**
- * Describes the reason that a particular IR temporary variable was generated. For example, it could
- * be generated to hold the return value of a function, or to hold the result of a `?:` operator
+ * A reason that a particular IR temporary variable was generated. For example, it could be
+ * generated to hold the return value of a function, or to hold the result of a `?:` operator
  * computed on each branch. The set of possible `TempVariableTag`s is language-dependent.
  */
 class TempVariableTag extends TTempVariableTag {

cpp/ql/src/semmle/code/cpp/ir/implementation/aliased_ssa/Instruction.qll

@@ -584,9 +584,9 @@ class ConditionalBranchInstruction extends Instruction {
 
   final Instruction getCondition() { result = getConditionOperand().getDef() }
 
-  final Instruction getTrueSuccessor() { result = getSuccessor(trueEdge()) }
+  final Instruction getTrueSuccessor() { result = getSuccessor(EdgeKind::trueEdge()) }
 
-  final Instruction getFalseSuccessor() { result = getSuccessor(falseEdge()) }
+  final Instruction getFalseSuccessor() { result = getSuccessor(EdgeKind::falseEdge()) }
 }
 
 class ExitFunctionInstruction extends Instruction {
@@ -906,7 +906,7 @@ class SwitchInstruction extends Instruction {
 
   final Instruction getACaseSuccessor() { exists(CaseEdge edge | result = getSuccessor(edge)) }
 
-  final Instruction getDefaultSuccessor() { result = getSuccessor(defaultEdge()) }
+  final Instruction getDefaultSuccessor() { result = getSuccessor(EdgeKind::defaultEdge()) }
 }
 
 /**

cpp/ql/src/semmle/code/cpp/ir/implementation/internal/OperandTag.qll

@@ -2,6 +2,7 @@
  * Defines the set of possible `OperandTag`s, which are used to identify the role each `Operand`
  * plays in the evaluation of its `Instruction`.
  */
+
 private import OperandTagInternal
 
 private newtype TOperandTag =
@@ -32,13 +33,13 @@ abstract class OperandTag extends TOperandTag {
   abstract string toString();
 
   /**
-   * Gets an integer representing the order in which this operand should appear in the operand list
-   * of an instruction when printing the IR.
+   * Gets an integer that represents where this this operand will appear in the operand list of an
+   * instruction when the IR is printed.
    */
   abstract int getSortOrder();
 
   /**
-   * Gets a label that will appear before the operand when printing the IR.
+   * Gets a label that will appear before the operand when the IR is printed.
    */
   string getLabel() { result = "" }
 }
@@ -59,7 +60,7 @@ abstract class RegisterOperandTag extends OperandTag { }
 abstract class TypedOperandTag extends MemoryOperandTag { }
 
 // Note: individual subtypes are listed in the order that the operands should
-// appear in the operand list of the instruction when printing.
+// appear in the operand list of the instruction when the IR is printed.
 /**
  * The address operand of an instruction that loads or stores a value from
  * memory (e.g. `Load`, `Store`, `InitializeParameter`, `IndirectReadSideEffect`).

cpp/ql/src/semmle/code/cpp/ir/implementation/raw/Instruction.qll

@@ -584,9 +584,9 @@ class ConditionalBranchInstruction extends Instruction {
 
   final Instruction getCondition() { result = getConditionOperand().getDef() }
 
-  final Instruction getTrueSuccessor() { result = getSuccessor(trueEdge()) }
+  final Instruction getTrueSuccessor() { result = getSuccessor(EdgeKind::trueEdge()) }
 
-  final Instruction getFalseSuccessor() { result = getSuccessor(falseEdge()) }
+  final Instruction getFalseSuccessor() { result = getSuccessor(EdgeKind::falseEdge()) }
 }
 
 class ExitFunctionInstruction extends Instruction {
@@ -906,7 +906,7 @@ class SwitchInstruction extends Instruction {
 
   final Instruction getACaseSuccessor() { exists(CaseEdge edge | result = getSuccessor(edge)) }
 
-  final Instruction getDefaultSuccessor() { result = getSuccessor(defaultEdge()) }
+  final Instruction getDefaultSuccessor() { result = getSuccessor(EdgeKind::defaultEdge()) }
 }
 
 /**

cpp/ql/src/semmle/code/cpp/ir/implementation/raw/internal/TranslatedCall.qll

@@ -375,7 +375,7 @@ class TranslatedAllocationSideEffects extends TranslatedSideEffects,
 
   override Instruction getInstructionSuccessor(InstructionTag tag, EdgeKind kind) {
     tag = OnlyInstructionTag() and
-    kind = gotoEdge() and
+    kind = EdgeKind::gotoEdge() and
     if exists(getChild(0))
     then result = getChild(0).getFirstInstruction()
     else result = getParent().getChildSuccessor(this)

cpp/ql/src/semmle/code/cpp/ir/implementation/raw/internal/TranslatedFunction.qll

@@ -720,7 +720,7 @@ class TranslatedReadEffect extends TranslatedElement, TTranslatedReadEffect {
 
   override Instruction getInstructionSuccessor(InstructionTag tag, EdgeKind edge) {
     tag = OnlyInstructionTag() and
-    edge = gotoEdge() and
+    edge = EdgeKind::gotoEdge() and
     result = getParent().getChildSuccessor(this)
   }
 

cpp/ql/src/semmle/code/cpp/ir/implementation/unaliased_ssa/Instruction.qll

@@ -584,9 +584,9 @@ class ConditionalBranchInstruction extends Instruction {
 
   final Instruction getCondition() { result = getConditionOperand().getDef() }
 
-  final Instruction getTrueSuccessor() { result = getSuccessor(trueEdge()) }
+  final Instruction getTrueSuccessor() { result = getSuccessor(EdgeKind::trueEdge()) }
 
-  final Instruction getFalseSuccessor() { result = getSuccessor(falseEdge()) }
+  final Instruction getFalseSuccessor() { result = getSuccessor(EdgeKind::falseEdge()) }
 }
 
 class ExitFunctionInstruction extends Instruction {
@@ -906,7 +906,7 @@ class SwitchInstruction extends Instruction {
 
   final Instruction getACaseSuccessor() { exists(CaseEdge edge | result = getSuccessor(edge)) }
 
-  final Instruction getDefaultSuccessor() { result = getSuccessor(defaultEdge()) }
+  final Instruction getDefaultSuccessor() { result = getSuccessor(EdgeKind::defaultEdge()) }
 }
 
 /**

cpp/ql/src/semmle/code/cpp/ir/internal/IntegerConstant.qll

@@ -1,6 +1,6 @@
 /**
- * Provides predicates for manipulating integer constants tracked by constant folding and similar
- * analyses.
+ * Provides predicates for manipulating integer constants that are tracked by constant folding and
+ * similar analyses.
  */
 
 /**