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diff --git a/build/clang-plugin/VariableUsageHelpers.h b/build/clang-plugin/VariableUsageHelpers.h
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+++ b/build/clang-plugin/VariableUsageHelpers.h
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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef VariableUsageHelpers_h__
+#define VariableUsageHelpers_h__
+
+#include "plugin.h"
+
+/// Returns a list of the statements where the given declaration is used as an
+/// rvalue (within the provided function).
+///
+/// WARNING: incomplete behaviour/implementation for general-purpose use outside
+/// of escapesFunction(). This only detects very basic usages (see
+/// implementation for more details).
+std::vector<const Stmt *> getUsageAsRvalue(const ValueDecl *ValueDeclaration,
+                                           const FunctionDecl *FuncDecl);
+
+/// This is the error enumeration for escapesFunction(), describing all the
+/// possible error cases.
+enum class EscapesFunctionError {
+  ConstructorDeclNotFound = 1,
+  FunctionDeclNotFound,
+  FunctionIsBuiltin,
+  FunctionIsVariadic,
+  ExprNotInCall,
+  NoParamForArg,
+  ArgAndParamNotPointers
+};
+
+/// Required by the std::error_code system to convert our enum into a general
+/// error code.
+std::error_code make_error_code(EscapesFunctionError);
+
+/// Returns a (statement, decl) tuple if an argument from an argument list
+/// escapes the function scope through globals/statics/other things. The
+/// statement is where the value escapes the function, while the declaration
+/// points to what it escapes through. If the argument doesn't escape the
+/// function, the tuple will only contain nullptrs.
+/// If the analysis runs into an unexpected error or into an unimplemented
+/// configuration, it will return an error_code of type EscapesFunctionError
+/// representing the precise issue.
+///
+/// WARNING: incomplete behaviour/implementation for general-purpose use outside
+/// of DanglingOnTemporaryChecker. This only covers a limited set of cases,
+/// mainly in terms of arguments and parameter types.
+ErrorOr<std::tuple<const Stmt *, const Decl *>>
+escapesFunction(const Expr *Arg, const FunctionDecl *FuncDecl,
+                const Expr *const *Arguments, unsigned NumArgs);
+
+/// Helper function taking a call expression.
+ErrorOr<std::tuple<const Stmt *, const Decl *>>
+escapesFunction(const Expr *Arg, const CallExpr *Call);
+
+/// Helper function taking a construct expression.
+ErrorOr<std::tuple<const Stmt *, const Decl *>>
+escapesFunction(const Expr *Arg, const CXXConstructExpr *Construct);
+
+/// Helper function taking an operator call expression.
+ErrorOr<std::tuple<const Stmt *, const Decl *>>
+escapesFunction(const Expr *Arg, const CXXOperatorCallExpr *OpCall);
+
+#endif