Class Expr

A C/C++ expression.

This is the root QL class for all expressions.

Import path

import cpp

Direct supertypes

Indirect supertypes

Known direct subtypes

Predicates

getAChild	Gets a child of this expression.
getActualType	Gets the type of this expression, after any implicit conversions and explicit casts, and after resolving typedefs.
getAnImplicitDestructorCall	Gets a compiler-generated destructor call that is performed after this expression.
getChild	Gets the nth child of this expression.
getControlFlowScope	Gets the function containing this control-flow node.
getConversion	Gets the conversion associated with this expression, if any.
getConversionString	Gets a string describing the conversion associated with this expression, or "" if there is none.
getEnclosingBlock	Gets the nearest enclosing set of curly braces around this expression in the source, if any.
getEnclosingDeclaration	Gets the enclosing variable or function of this expression.
getEnclosingFunction	Gets the enclosing function of this expression, if any.
getEnclosingStmt	Gets the smallest statement containing this control-flow node.
getEnclosingVariable	Gets the enclosing variable of this expression, if any.
getExplicitlyConverted	Gets this expression with all of its explicit casts, but none of its implicit casts. More precisely this takes conversions up to the last explicit cast (there may be implicit conversions along the way), but does not include conversions after the last explicit cast.
getFullyConverted	Gets the fully converted form of this expression, including all type casts and other conversions.
getImplicitDestructorCall	Gets the `n`th compiler-generated destructor call that is performed after this expression, in order of destruction.
getImplicitlyConverted	Gets this expression with all of its initial implicit casts, but none of its explicit casts. More precisely, this takes all implicit conversions up to (but not including) the first explicit cast (if any).
getLocation	Gets the location of this expression.
getNumChild	Gets the number of direct children of this expression.
getParent	Gets the parent of this expression, if any.
getParentWithConversions	Gets the parent of this expression, if any, in an alternative syntax tree that has `Conversion`s as part of the tree.
getPrecedence	Gets the precedence of the main operator of this expression; higher precedence binds tighter.
getType	Gets the type of this expression.
getUnconverted	Gets the unique non-`Conversion` expression `e` for which `this = e.getConversion*()`.
getUnderlyingType	Gets the type of this expression after typedefs have been resolved.
getUnspecifiedType	Gets the type of this expression after specifiers have been deeply stripped and typedefs have been resolved.
getValue	Gets the value of this expression, if it is a constant.
getValueCategoryString	Gets a string representation of the value category of the expression. This is intended only for debugging. The possible values are:
getValueText	Gets the source text for the value of this expression, if it is a constant.
hasChild	Holds if e is the nth child of this expression.
hasConversion	Holds if this expression has a conversion.
hasExplicitConversion	Holds if this expression has an explicit conversion.
hasImplicitConversion	Holds if this expression has an implicit conversion.
hasLValueToRValueConversion	Holds if this expression has undergone an lvalue-to-rvalue conversion to extract its value. for example: `y = x;` The `VariableAccess` for `x` is a prvalue, and `hasLValueToRValueConversion()` holds because the value of `x` was loaded from the location of `x`. The `VariableAccess` for `y` is an lvalue, and `hasLValueToRValueConversion()` does not hold because the value of `y` was not extracted.
isCompilerGenerated	Holds if this is an auxiliary expression generated by the compiler.
isConstant	Holds if this expression has a value that can be determined at compile time.
isGLValueCategory	Holds if this expression is a glvalue. A glvalue is either an lvalue or an xvalue.
isLValue	Holds if this expression is an lvalue, in the sense of having an address.
isLValueCategory	Holds if this expression is an lvalue. An lvalue is an expression that represents a location, rather than a value. See [basic.lval] for more about lvalues.
isPRValueCategory	Holds if this expression is a prvalue. A prvalue is an expression that represents a value, rather than a location. See [basic.lval] for more about prvalues.
isParenthesised	Holds if this expression is parenthesised.
isPure	Holds if this expression is side-effect free (conservative approximation). This predicate cannot be overridden; override mayBeImpure() instead.
isRValueCategory	Holds if this expression is an rvalue. An rvalue is either a prvalue or an xvalue.
isUnevaluated	Holds if this expression will not be evaluated because of its context, such as an expression inside a sizeof.
isXValueCategory	Holds if this expression is an xvalue. An xvalue is a location whose lifetime is about to end (e.g. an rvalue reference returned from a function call). See [basic.lval] for more about xvalues.
mayBeGloballyImpure	Holds if it is possible that the expression may be impure. If we are not sure, then it holds. Unlike `mayBeImpure()`, this predicate does not consider modifications to temporary local variables to be impure. If you call a function in which nothing may be globally impure then the function as a whole will have no side-effects, even if it mutates its own fresh stack variables.
mayBeImpure	Holds if it is possible that the expression may be impure. If we are not sure, then it holds.
toString	Gets a textual representation of this expression.

Inherited predicates

findRootCause	Gets the source of this element: either itself or a macro that expanded to this element.	from Element
fromSource	Holds if this element may be from source. This predicate holds for all elements, except for those in the dummy file, whose name is the empty string. The dummy file contains declarations that are built directly into the compiler.	from Element
getAFalseSuccessor	Gets a node such that the control-flow edge `(this, result)` may be taken when this expression is false.	from ControlFlowNode
getAPredecessor	Gets a direct predecessor of this control-flow node, if any.	from ControlFlowNode
getAPrimaryQlClass	Gets the name of a primary CodeQL class to which this element belongs.	from ElementBase
getASuccessor	Gets a direct successor of this control-flow node, if any.	from ControlFlowNode
getATrueSuccessor	Gets a node such that the control-flow edge `(this, result)` may be taken when this expression is true.	from ControlFlowNode
getBasicBlock	Gets the `BasicBlock` containing this control-flow node.	from ControlFlowNode
getEnclosingElement	Gets the closest `Element` enclosing this one.	from Element
getFile	Gets the primary file where this element occurs.	from Element
getParentScope	Gets the parent scope of this `Element`, if any. A scope is a `Type` (`Class` / `Enum`), a `Namespace`, a `BlockStmt`, a `Function`, or certain kinds of `Statement`.	from Element
getPrimaryQlClasses	Gets a comma-separated list of the names of the primary CodeQL classes to which this element belongs.	from ElementBase
isAffectedByMacro	Holds if this element is affected in any way by a macro. All elements that are totally or partially generated by a macro are included, so this is a super-set of `isInMacroExpansion`.	from Element
isCondition	Holds if this node is the top-level expression of a conditional statement, meaning that `this.getATrueSuccessor()` or `this.getAFalseSuccessor()` will have a result.	from ControlFlowNode
isFromTemplateInstantiation	Holds if this `Element` is a part of a template instantiation (but not the template itself).	from Element
isFromUninstantiatedTemplate	Holds if this `Element` is part of a template `template` (not if it is part of an instantiation of `template`). This means it is represented in the database purely as syntax and without guarantees on the presence or correctness of type-based operations such as implicit conversions.	from Element
isInMacroExpansion	Holds if this element comes from a macro expansion. Only elements that are entirely generated by a macro are included - for elements that partially come from a macro, see `isAffectedByMacro`.	from Element