Merge pull request #8484 from hvitved/ruby/constant-value-rework

Ruby: Rework `getConstantValue` implementation

Author: hvitved

ruby/ql/lib/codeql/ruby/ast/Constant.qll

@@ -224,23 +224,7 @@ class ConstantReadAccess extends ConstantAccess {
    *
    * the value being read at `M::CONST` is `"const"`.
    */
-  Expr getValue() {
-    not exists(this.getScopeExpr()) and
-    result = lookupConst(this.getEnclosingModule+().getModule(), this.getName()) and
-    // For now, we restrict the scope of top-level declarations to their file.
-    // This may remove some plausible targets, but also removes a lot of
-    // implausible targets
-    if result.getEnclosingModule() instanceof Toplevel
-    then result.getFile() = this.getFile()
-    else any()
-    or
-    this.hasGlobalScope() and
-    result = lookupConst(TResolved("Object"), this.getName())
-    or
-    result = lookupConst(resolveConstantReadAccess(this.getScopeExpr()), this.getName())
-  }
-
-  final override ConstantValue getConstantValue() { result = this.getValue().getConstantValue() }
+  Expr getValue() { result = getConstantReadAccessValue(this) }
 
   final override string getAPrimaryQlClass() { result = "ConstantReadAccess" }
 }

ruby/ql/lib/codeql/ruby/ast/Expr.qll

@@ -2,6 +2,7 @@ private import codeql.ruby.AST
 private import codeql.ruby.CFG
 private import codeql.ruby.ast.Constant
 private import internal.AST
+private import internal.Constant
 private import internal.Expr
 private import internal.TreeSitter
 
@@ -19,9 +20,7 @@ class Expr extends Stmt, TExpr {
   deprecated string getValueText() { result = this.getConstantValue().toString() }
 
   /** Gets the constant value of this expression, if any. */
-  ConstantValue getConstantValue() {
-    forex(CfgNodes::ExprCfgNode n | n = this.getAControlFlowNode() | result = n.getConstantValue())
-  }
+  ConstantValue getConstantValue() { result = getConstantValueExpr(this) }
 }
 
 /** DEPRECATED: Use `SelfVariableAccess` instead. */