Add exprt::with_source_location with source_locationt parameter

We already supported the fluent-style with_source_location for copying
from another expression (since 917f9a0). Now also support passing a
source location directly.

Author: tautschnig

src/util/expr.h

@@ -97,6 +97,30 @@ class exprt:public irept
   const operandst &operands() const
   { return (const operandst &)get_sub(); }
 
+  /// Add the source location from \p other, if it has any.
+  template <typename T>
+  T &with_source_location(source_locationt location) &
+  {
+    static_assert(
+      std::is_base_of<exprt, T>::value,
+      "The template argument T must be derived from exprt.");
+    if(location.is_not_nil())
+      add_source_location() = std::move(location);
+    return *static_cast<T *>(this);
+  }
+
+  /// Add the source location from \p other, if it has any.
+  template <typename T>
+  T &&with_source_location(source_locationt location) &&
+  {
+    static_assert(
+      std::is_base_of<exprt, T>::value,
+      "The template argument T must be derived from exprt.");
+    if(location.is_not_nil())
+      add_source_location() = std::move(location);
+    return std::move(*static_cast<T *>(this));
+  }
+
   /// Add the source location from \p other, if it has any.
   template <typename T>
   T &with_source_location(const exprt &other) &