Revert #8360, "Add CompileTimeConstantExpr.getStringified method"

java/ql/lib/change-notes/2022-03-07-get-stringified-value.md

@@ -1,6 +0,0 @@
----
-category: minorAnalysis
----
- * Add new predicate `CompileTimeConstantExpr.getStringifiedValue` which attempts to compute the
-   `String.valueOf` string rendering of a constant expression. This predicate is now used to 
-   compute the string value of an `AddExpr` that has the type `String`.

java/ql/lib/semmle/code/java/Expr.qll

@@ -161,38 +161,6 @@ class CompileTimeConstantExpr extends Expr {
     )
   }
 
-  /**
-   * Gets the stringified value of this expression, where possible.
-   *
-   * The stringified version of a compile-time constant expression is the equivalent to
-   * the result of calling `String.valueOf(expr)` on the expression.
-   *
-   * Note that this does not handle the following cases:
-   *
-   * - mathematical computations of type `long`, `float`, or `double`.
-   */
-  pragma[nomagic]
-  string getStringifiedValue() {
-    result = this.getStringValue()
-    or
-    result = this.(Literal).getValue()
-    or
-    result = this.getBooleanValue().toString()
-    or
-    result = this.getIntValue().toString()
-    or
-    // Ternary conditional, with compile-time constant condition.
-    exists(ConditionalExpr ce, boolean condition |
-      ce = this and
-      condition = ce.getCondition().(CompileTimeConstantExpr).getBooleanValue() and
-      result = ce.getBranchExpr(condition).(CompileTimeConstantExpr).getStringifiedValue()
-    )
-    or
-    exists(Variable v | this = v.getAnAccess() |
-      result = v.getInitializer().(CompileTimeConstantExpr).getStringifiedValue()
-    )
-  }
-
   /**
    * Gets the string value of this expression, where possible.
    */
@@ -200,11 +168,11 @@ class CompileTimeConstantExpr extends Expr {
   string getStringValue() {
     result = this.(StringLiteral).getValue()
     or
-    this.getType() instanceof TypeString and // When the expression type is `String`
+    result = this.(CharacterLiteral).getValue()
+    or
     result =
-      // Then the resultant string is the addition of both operands stringified value, regardless of type.
-      this.(AddExpr).getLeftOperand().(CompileTimeConstantExpr).getStringifiedValue() +
-        this.(AddExpr).getRightOperand().(CompileTimeConstantExpr).getStringifiedValue()
+      this.(AddExpr).getLeftOperand().(CompileTimeConstantExpr).getStringValue() +
+        this.(AddExpr).getRightOperand().(CompileTimeConstantExpr).getStringValue()
     or
     // Ternary conditional, with compile-time constant condition.
     exists(ConditionalExpr ce, boolean condition |