Remove unused includes list, functional from expr.h

This header file is widely used, and dragging in useless includes unnecessarily
slows down compilation. Required fixes to files that actually do use std::list.

Author: tautschnig

src/ansi-c/ansi_c_convert_type.h

@@ -12,6 +12,8 @@ Author: Daniel Kroening, [email protected]
 #ifndef CPROVER_ANSI_C_ANSI_C_CONVERT_TYPE_H
 #define CPROVER_ANSI_C_ANSI_C_CONVERT_TYPE_H
 
+#include <list>
+
 #include <util/message.h>
 
 #include "c_qualifiers.h"

src/assembler/assembler_parser.cpp

@@ -8,8 +8,6 @@ Author: Daniel Kroening, [email protected]
 
 #include "assembler_parser.h"
 
-#include <iostream>
-
 assembler_parsert assembler_parser;
 
 extern char *yyassemblertext;

src/assembler/assembler_parser.h

@@ -11,7 +11,8 @@ Author: Daniel Kroening, [email protected]
 #define CPROVER_ASSEMBLER_ASSEMBLER_PARSER_H
 
 #include <util/parser.h>
-#include <util/expr.h>
+
+#include <list>
 
 int yyassemblerlex();
 int yyassemblererror(const std::string &error);

src/solvers/flattening/arrays.h

@@ -12,6 +12,7 @@ Author: Daniel Kroening, [email protected]
 #ifndef CPROVER_SOLVERS_FLATTENING_ARRAYS_H
 #define CPROVER_SOLVERS_FLATTENING_ARRAYS_H
 
+#include <list>
 #include <set>
 
 #include <util/union_find.h>

src/solvers/prop/cover_goals.cpp

@@ -11,9 +11,8 @@ Author: Daniel Kroening, [email protected]
 
 #include "cover_goals.h"
 
-#include <util/threeval.h>
-
 #include "literal_expr.h"
+#include "prop_conv.h"
 
 cover_goalst::~cover_goalst()
 {

src/solvers/prop/cover_goals.h

@@ -12,9 +12,11 @@ Author: Daniel Kroening, [email protected]
 #ifndef CPROVER_SOLVERS_PROP_COVER_GOALS_H
 #define CPROVER_SOLVERS_PROP_COVER_GOALS_H
 
+#include <list>
+
 #include <util/message.h>
 
-#include "prop_conv.h"
+class prop_convt;
 
 /// Try to cover some given set of goals incrementally. This can be seen as a
 /// heuristic variant of SAT-based set-cover. No minimality guarantee.

src/util/expr.h

@@ -15,9 +15,6 @@ Author: Daniel Kroening, [email protected]
 #include "validate_types.h"
 #include "validation_mode.h"
 
-#include <functional>
-#include <list>
-
 #define forall_operands(it, expr) \
   if((expr).has_operands()) /* NOLINT(readability/braces) */ \
     for(exprt::operandst::const_iterator it=(expr).operands().begin(), \