Update various forward declarations to use typedef

There are a number of forward declarations that use struct but not the
customary typedef, because that could have led to repeat typedefs,
which was not allowed.  This is now allowed in C11, so we can update
these to provide the typedefs as well, so that the later uses of the
types look more consistent.

Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/10d32190-f31b-40a5-b177-11db55597355@eisentraut.org

src/include/commands/tablecmds.h

@@ -21,7 +21,8 @@
 #include "storage/lock.h"
 #include "utils/relcache.h"
 
-struct AlterTableUtilityContext;	/* avoid including tcop/utility.h here */
+typedef struct AlterTableUtilityContext AlterTableUtilityContext;	/* avoid including
+																	 * tcop/utility.h here */
 
 
 extern ObjectAddress DefineRelation(CreateStmt *stmt, char relkind, Oid ownerId,
@@ -34,7 +35,7 @@ extern void RemoveRelations(DropStmt *drop);
 extern Oid	AlterTableLookupRelation(AlterTableStmt *stmt, LOCKMODE lockmode);
 
 extern void AlterTable(AlterTableStmt *stmt, LOCKMODE lockmode,
-					   struct AlterTableUtilityContext *context);
+					   AlterTableUtilityContext *context);
 
 extern LOCKMODE AlterTableGetLockLevel(List *cmds);
 

src/include/common/string.h

@@ -12,7 +12,8 @@
 
 #include <signal.h>
 
-struct StringInfoData;			/* avoid including stringinfo.h here */
+typedef struct StringInfoData *StringInfo;	/* avoid including stringinfo.h
+											 * here */
 
 typedef struct PromptInterruptContext
 {
@@ -32,8 +33,8 @@ extern bool pg_is_ascii(const char *str);
 
 /* functions in src/common/pg_get_line.c */
 extern char *pg_get_line(FILE *stream, PromptInterruptContext *prompt_ctx);
-extern bool pg_get_line_buf(FILE *stream, struct StringInfoData *buf);
-extern bool pg_get_line_append(FILE *stream, struct StringInfoData *buf,
+extern bool pg_get_line_buf(FILE *stream, StringInfo buf);
+extern bool pg_get_line_append(FILE *stream, StringInfo buf,
 							   PromptInterruptContext *prompt_ctx);
 
 /* functions in src/common/sprompt.c */

src/include/executor/executor.h

@@ -100,12 +100,12 @@ extern PGDLLIMPORT ExecutorCheckPerms_hook_type ExecutorCheckPerms_hook;
 /*
  * prototypes from functions in execAmi.c
  */
-struct Path;					/* avoid including pathnodes.h here */
+typedef struct Path Path;		/* avoid including pathnodes.h here */
 
 extern void ExecReScan(PlanState *node);
 extern void ExecMarkPos(PlanState *node);
 extern void ExecRestrPos(PlanState *node);
-extern bool ExecSupportsMarkRestore(struct Path *pathnode);
+extern bool ExecSupportsMarkRestore(Path *pathnode);
 extern bool ExecSupportsBackwardScan(Plan *node);
 extern bool ExecMaterializesOutput(NodeTag plantype);
 

src/include/executor/tablefunc.h

@@ -14,7 +14,7 @@
 #define _TABLEFUNC_H
 
 /* Forward-declare this to avoid including execnodes.h here */
-struct TableFuncScanState;
+typedef struct TableFuncScanState TableFuncScanState;
 
 /*
  * TableFuncRoutine holds function pointers used for generating content of
@@ -51,17 +51,17 @@ struct TableFuncScanState;
  */
 typedef struct TableFuncRoutine
 {
-	void		(*InitOpaque) (struct TableFuncScanState *state, int natts);
-	void		(*SetDocument) (struct TableFuncScanState *state, Datum value);
-	void		(*SetNamespace) (struct TableFuncScanState *state, const char *name,
+	void		(*InitOpaque) (TableFuncScanState *state, int natts);
+	void		(*SetDocument) (TableFuncScanState *state, Datum value);
+	void		(*SetNamespace) (TableFuncScanState *state, const char *name,
 								 const char *uri);
-	void		(*SetRowFilter) (struct TableFuncScanState *state, const char *path);
-	void		(*SetColumnFilter) (struct TableFuncScanState *state,
+	void		(*SetRowFilter) (TableFuncScanState *state, const char *path);
+	void		(*SetColumnFilter) (TableFuncScanState *state,
 									const char *path, int colnum);
-	bool		(*FetchRow) (struct TableFuncScanState *state);
-	Datum		(*GetValue) (struct TableFuncScanState *state, int colnum,
+	bool		(*FetchRow) (TableFuncScanState *state);
+	Datum		(*GetValue) (TableFuncScanState *state, int colnum,
 							 Oid typid, int32 typmod, bool *isnull);
-	void		(*DestroyOpaque) (struct TableFuncScanState *state);
+	void		(*DestroyOpaque) (TableFuncScanState *state);
 } TableFuncRoutine;
 
 #endif							/* _TABLEFUNC_H */

src/include/nodes/execnodes.h

@@ -49,15 +49,13 @@
 #include "utils/tuplesort.h"
 #include "utils/tuplestore.h"
 
-struct PlanState;				/* forward references in this file */
-struct ParallelHashJoinState;
-struct ExecRowMark;
-struct ExprState;
-struct ExprContext;
-struct RangeTblEntry;			/* avoid including parsenodes.h here */
-struct ExprEvalStep;			/* avoid including execExpr.h everywhere */
-struct CopyMultiInsertBuffer;
-struct LogicalTapeSet;
+/*
+ * forward references in this file
+ */
+typedef struct PlanState PlanState;
+typedef struct ExecRowMark ExecRowMark;
+typedef struct ExprState ExprState;
+typedef struct ExprContext ExprContext;
 
 
 /* ----------------
@@ -67,8 +65,8 @@ struct LogicalTapeSet;
  * It contains instructions (in ->steps) to evaluate the expression.
  * ----------------
  */
-typedef Datum (*ExprStateEvalFunc) (struct ExprState *expression,
-									struct ExprContext *econtext,
+typedef Datum (*ExprStateEvalFunc) (ExprState *expression,
+									ExprContext *econtext,
 									bool *isNull);
 
 /* Bits in ExprState->flags (see also execExpr.h for private flag bits): */
@@ -131,7 +129,7 @@ typedef struct ExprState
 	int			steps_alloc;	/* allocated length of steps array */
 
 #define FIELDNO_EXPRSTATE_PARENT 11
-	struct PlanState *parent;	/* parent PlanState node, if any */
+	PlanState  *parent;			/* parent PlanState node, if any */
 	ParamListInfo ext_params;	/* for compiling PARAM_EXTERN nodes */
 
 	Datum	   *innermost_caseval;
@@ -638,8 +636,8 @@ typedef struct ResultRelInfo
  */
 typedef struct AsyncRequest
 {
-	struct PlanState *requestor;	/* Node that wants a tuple */
-	struct PlanState *requestee;	/* Node from which a tuple is wanted */
+	PlanState  *requestor;		/* Node that wants a tuple */
+	PlanState  *requestee;		/* Node from which a tuple is wanted */
 	int			request_index;	/* Scratch space for requestor */
 	bool		callback_pending;	/* Callback is needed */
 	bool		request_complete;	/* Request complete, result valid */
@@ -665,8 +663,8 @@ typedef struct EState
 	Index		es_range_table_size;	/* size of the range table arrays */
 	Relation   *es_relations;	/* Array of per-range-table-entry Relation
 								 * pointers, or NULL if not yet opened */
-	struct ExecRowMark **es_rowmarks;	/* Array of per-range-table-entry
-										 * ExecRowMarks, or NULL if none */
+	ExecRowMark **es_rowmarks;	/* Array of per-range-table-entry
+								 * ExecRowMarks, or NULL if none */
 	List	   *es_rteperminfos;	/* List of RTEPermissionInfo */
 	PlannedStmt *es_plannedstmt;	/* link to top of plan tree */
 	List	   *es_part_prune_infos;	/* List of PartitionPruneInfo */
@@ -1006,8 +1004,8 @@ typedef struct SubPlanState
 {
 	NodeTag		type;
 	SubPlan    *subplan;		/* expression plan node */
-	struct PlanState *planstate;	/* subselect plan's state tree */
-	struct PlanState *parent;	/* parent plan node's state tree */
+	PlanState  *planstate;		/* subselect plan's state tree */
+	PlanState  *parent;			/* parent plan node's state tree */
 	ExprState  *testexpr;		/* state of combining expression */
 	HeapTuple	curTuple;		/* copy of most recent tuple from subplan */
 	Datum		curArray;		/* most recent array from ARRAY() subplan */
@@ -1143,7 +1141,7 @@ typedef struct JsonExprState
  * if no more tuples are available.
  * ----------------
  */
-typedef TupleTableSlot *(*ExecProcNodeMtd) (struct PlanState *pstate);
+typedef TupleTableSlot *(*ExecProcNodeMtd) (PlanState *pstate);
 
 /* ----------------
  *		PlanState node
@@ -1180,8 +1178,8 @@ typedef struct PlanState
 	 * subPlan list, which does not exist in the plan tree).
 	 */
 	ExprState  *qual;			/* boolean qual condition */
-	struct PlanState *lefttree; /* input plan tree(s) */
-	struct PlanState *righttree;
+	PlanState  *lefttree;		/* input plan tree(s) */
+	PlanState  *righttree;
 
 	List	   *initPlan;		/* Init SubPlanState nodes (un-correlated expr
 								 * subselects) */

src/include/nodes/nodeFuncs.h

@@ -15,7 +15,7 @@
 
 #include "nodes/parsenodes.h"
 
-struct PlanState;				/* avoid including execnodes.h too */
+typedef struct PlanState PlanState; /* avoid including execnodes.h too */
 
 
 /* flags bits for query_tree_walker and query_tree_mutator */
@@ -38,7 +38,7 @@ typedef bool (*check_function_callback) (Oid func_id, void *context);
 
 /* callback functions for tree walkers */
 typedef bool (*tree_walker_callback) (Node *node, void *context);
-typedef bool (*planstate_tree_walker_callback) (struct PlanState *planstate,
+typedef bool (*planstate_tree_walker_callback) (PlanState *planstate,
 												void *context);
 
 /* callback functions for tree mutators */
@@ -217,7 +217,7 @@ extern bool raw_expression_tree_walker_impl(Node *node,
 											tree_walker_callback walker,
 											void *context);
 
-extern bool planstate_tree_walker_impl(struct PlanState *planstate,
+extern bool planstate_tree_walker_impl(PlanState *planstate,
 									   planstate_tree_walker_callback walker,
 									   void *context);
 

src/include/nodes/params.h

@@ -14,11 +14,10 @@
 #ifndef PARAMS_H
 #define PARAMS_H
 
-/* Forward declarations, to avoid including other headers */
-struct Bitmapset;
-struct ExprState;
-struct Param;
-struct ParseState;
+/* to avoid including other headers */
+typedef struct ExprState ExprState;
+typedef struct Param Param;
+typedef struct ParseState ParseState;
 
 
 /*
@@ -101,11 +100,11 @@ typedef ParamExternData *(*ParamFetchHook) (ParamListInfo params,
 											int paramid, bool speculative,
 											ParamExternData *workspace);
 
-typedef void (*ParamCompileHook) (ParamListInfo params, struct Param *param,
-								  struct ExprState *state,
+typedef void (*ParamCompileHook) (ParamListInfo params, Param *param,
+								  ExprState *state,
 								  Datum *resv, bool *resnull);
 
-typedef void (*ParserSetupHook) (struct ParseState *pstate, void *arg);
+typedef void (*ParserSetupHook) (ParseState *pstate, void *arg);
 
 typedef struct ParamListInfoData
 {

src/include/nodes/subscripting.h

@@ -15,10 +15,10 @@
 
 #include "nodes/primnodes.h"
 
-/* Forward declarations, to avoid including other headers */
-struct ParseState;
-struct SubscriptingRefState;
-struct SubscriptExecSteps;
+/* to avoid including other headers */
+typedef struct ParseState ParseState;
+typedef struct SubscriptingRefState SubscriptingRefState;
+typedef struct SubscriptExecSteps SubscriptExecSteps;
 
 /*
  * The SQL-visible function that defines a subscripting method is declared
@@ -94,7 +94,7 @@ struct SubscriptExecSteps;
  */
 typedef void (*SubscriptTransform) (SubscriptingRef *sbsref,
 									List *indirection,
-									struct ParseState *pstate,
+									ParseState *pstate,
 									bool isSlice,
 									bool isAssignment);
 
@@ -151,8 +151,8 @@ typedef void (*SubscriptTransform) (SubscriptingRef *sbsref,
  * Set the relevant pointers to NULL for any omitted methods.
  */
 typedef void (*SubscriptExecSetup) (const SubscriptingRef *sbsref,
-									struct SubscriptingRefState *sbsrefstate,
-									struct SubscriptExecSteps *methods);
+									SubscriptingRefState *sbsrefstate,
+									SubscriptExecSteps *methods);
 
 /* Struct returned by the SQL-visible subscript handler function */
 typedef struct SubscriptRoutines

src/include/nodes/supportnodes.h

@@ -35,10 +35,10 @@
 
 #include "nodes/plannodes.h"
 
-struct PlannerInfo;				/* avoid including pathnodes.h here */
-struct IndexOptInfo;
-struct SpecialJoinInfo;
-struct WindowClause;
+typedef struct PlannerInfo PlannerInfo; /* avoid including pathnodes.h here */
+typedef struct IndexOptInfo IndexOptInfo;
+typedef struct SpecialJoinInfo SpecialJoinInfo;
+typedef struct WindowClause WindowClause;
 
 /*
  * The Simplify request allows the support function to perform plan-time
@@ -65,7 +65,7 @@ typedef struct SupportRequestSimplify
 {
 	NodeTag		type;
 
-	struct PlannerInfo *root;	/* Planner's infrastructure */
+	PlannerInfo *root;			/* Planner's infrastructure */
 	FuncExpr   *fcall;			/* Function call to be simplified */
 } SupportRequestSimplify;
 
@@ -93,14 +93,14 @@ typedef struct SupportRequestSelectivity
 	NodeTag		type;
 
 	/* Input fields: */
-	struct PlannerInfo *root;	/* Planner's infrastructure */
+	PlannerInfo *root;			/* Planner's infrastructure */
 	Oid			funcid;			/* function we are inquiring about */
 	List	   *args;			/* pre-simplified arguments to function */
 	Oid			inputcollid;	/* function's input collation */
 	bool		is_join;		/* is this a join or restriction case? */
 	int			varRelid;		/* if restriction, RTI of target relation */
 	JoinType	jointype;		/* if join, outer join type */
-	struct SpecialJoinInfo *sjinfo; /* if outer join, info about join */
+	SpecialJoinInfo *sjinfo;	/* if outer join, info about join */
 
 	/* Output fields: */
 	Selectivity selectivity;	/* returned selectivity estimate */
@@ -133,7 +133,7 @@ typedef struct SupportRequestCost
 	NodeTag		type;
 
 	/* Input fields: */
-	struct PlannerInfo *root;	/* Planner's infrastructure (could be NULL) */
+	PlannerInfo *root;			/* Planner's infrastructure (could be NULL) */
 	Oid			funcid;			/* function we are inquiring about */
 	Node	   *node;			/* parse node invoking function, or NULL */
 
@@ -160,7 +160,7 @@ typedef struct SupportRequestRows
 	NodeTag		type;
 
 	/* Input fields: */
-	struct PlannerInfo *root;	/* Planner's infrastructure (could be NULL) */
+	PlannerInfo *root;			/* Planner's infrastructure (could be NULL) */
 	Oid			funcid;			/* function we are inquiring about */
 	Node	   *node;			/* parse node invoking function */
 
@@ -225,11 +225,11 @@ typedef struct SupportRequestIndexCondition
 	NodeTag		type;
 
 	/* Input fields: */
-	struct PlannerInfo *root;	/* Planner's infrastructure */
+	PlannerInfo *root;			/* Planner's infrastructure */
 	Oid			funcid;			/* function we are inquiring about */
 	Node	   *node;			/* parse node invoking function */
 	int			indexarg;		/* index of function arg matching indexcol */
-	struct IndexOptInfo *index; /* planner's info about target index */
+	IndexOptInfo *index;		/* planner's info about target index */
 	int			indexcol;		/* index of target index column (0-based) */
 	Oid			opfamily;		/* index column's operator family */
 	Oid			indexcollation; /* index column's collation */
@@ -293,7 +293,7 @@ typedef struct SupportRequestWFuncMonotonic
 
 	/* Input fields: */
 	WindowFunc *window_func;	/* Pointer to the window function data */
-	struct WindowClause *window_clause; /* Pointer to the window clause data */
+	WindowClause *window_clause;	/* Pointer to the window clause data */
 
 	/* Output fields: */
 	MonotonicFunction monotonic;
@@ -336,7 +336,7 @@ typedef struct SupportRequestOptimizeWindowClause
 
 	/* Input fields: */
 	WindowFunc *window_func;	/* Pointer to the window function data */
-	struct WindowClause *window_clause; /* Pointer to the window clause data */
+	WindowClause *window_clause;	/* Pointer to the window clause data */
 
 	/* Input/Output fields: */
 	int			frameOptions;	/* New frameOptions, or left untouched if no

src/include/optimizer/optimizer.h

@@ -35,9 +35,9 @@ typedef struct IndexOptInfo IndexOptInfo;
 typedef struct SpecialJoinInfo SpecialJoinInfo;
 
 /* It also seems best not to include plannodes.h, params.h, or htup.h here */
-struct PlannedStmt;
-struct ParamListInfoData;
-struct HeapTupleData;
+typedef struct PlannedStmt PlannedStmt;
+typedef struct ParamListInfoData *ParamListInfo;
+typedef struct HeapTupleData *HeapTuple;
 
 
 /* in path/clausesel.c: */
@@ -102,9 +102,9 @@ extern PGDLLIMPORT int debug_parallel_query;
 extern PGDLLIMPORT bool parallel_leader_participation;
 extern PGDLLIMPORT bool enable_distinct_reordering;
 
-extern struct PlannedStmt *planner(Query *parse, const char *query_string,
-								   int cursorOptions,
-								   struct ParamListInfoData *boundParams);
+extern PlannedStmt *planner(Query *parse, const char *query_string,
+							int cursorOptions,
+							ParamListInfo boundParams);
 
 extern Expr *expression_planner(Expr *expr);
 extern Expr *expression_planner_with_deps(Expr *expr,
@@ -147,7 +147,7 @@ extern bool var_is_nonnullable(PlannerInfo *root, Var *var, bool use_rel_info);
 
 extern List *expand_function_arguments(List *args, bool include_out_arguments,
 									   Oid result_type,
-									   struct HeapTupleData *func_tuple);
+									   HeapTuple func_tuple);
 
 extern ScalarArrayOpExpr *make_SAOP_expr(Oid oper, Node *leftexpr,
 										 Oid coltype, Oid arraycollid,

src/include/parser/parse_utilcmd.h

@@ -16,7 +16,7 @@
 
 #include "parser/parse_node.h"
 
-struct AttrMap;					/* avoid including attmap.h here */
+typedef struct AttrMap AttrMap; /* avoid including attmap.h here */
 
 
 extern List *transformCreateStmt(CreateStmt *stmt, const char *queryString);
@@ -38,7 +38,7 @@ extern List *expandTableLikeClause(RangeVar *heapRel,
 								   TableLikeClause *table_like_clause);
 extern IndexStmt *generateClonedIndexStmt(RangeVar *heapRel,
 										  Relation source_idx,
-										  const struct AttrMap *attmap,
+										  const AttrMap *attmap,
 										  Oid *constraintOid);
 
 #endif							/* PARSE_UTILCMD_H */

src/include/partitioning/partbounds.h

@@ -15,7 +15,7 @@
 #include "parser/parse_node.h"
 #include "partitioning/partdefs.h"
 
-struct RelOptInfo;				/* avoid including pathnodes.h here */
+typedef struct RelOptInfo RelOptInfo;	/* avoid including pathnodes.h here */
 
 
 /*
@@ -114,8 +114,8 @@ extern PartitionBoundInfo partition_bounds_copy(PartitionBoundInfo src,
 extern PartitionBoundInfo partition_bounds_merge(int partnatts,
 												 FmgrInfo *partsupfunc,
 												 Oid *partcollation,
-												 struct RelOptInfo *outer_rel,
-												 struct RelOptInfo *inner_rel,
+												 RelOptInfo *outer_rel,
+												 RelOptInfo *inner_rel,
 												 JoinType jointype,
 												 List **outer_parts,
 												 List **inner_parts);

src/include/partitioning/partprune.h

@@ -17,8 +17,8 @@
 #include "nodes/execnodes.h"
 #include "partitioning/partdefs.h"
 
-struct PlannerInfo;				/* avoid including pathnodes.h here */
-struct RelOptInfo;
+typedef struct PlannerInfo PlannerInfo; /* avoid including pathnodes.h here */
+typedef struct RelOptInfo RelOptInfo;
 
 
 /*
@@ -70,11 +70,11 @@ typedef struct PartitionPruneContext
 #define PruneCxtStateIdx(partnatts, step_id, keyno) \
 	((partnatts) * (step_id) + (keyno))
 
-extern int	make_partition_pruneinfo(struct PlannerInfo *root,
-									 struct RelOptInfo *parentrel,
+extern int	make_partition_pruneinfo(PlannerInfo *root,
+									 RelOptInfo *parentrel,
 									 List *subpaths,
 									 List *prunequal);
-extern Bitmapset *prune_append_rel_partitions(struct RelOptInfo *rel);
+extern Bitmapset *prune_append_rel_partitions(RelOptInfo *rel);
 extern Bitmapset *get_matching_partitions(PartitionPruneContext *context,
 										  List *pruning_steps);
 

src/include/rewrite/rewriteManip.h

@@ -17,7 +17,7 @@
 #include "nodes/parsenodes.h"
 #include "nodes/pathnodes.h"
 
-struct AttrMap;					/* avoid including attmap.h here */
+typedef struct AttrMap AttrMap; /* avoid including attmap.h here */
 
 
 typedef struct replace_rte_variables_context replace_rte_variables_context;
@@ -101,7 +101,7 @@ extern Node *replace_rte_variables_mutator(Node *node,
 
 extern Node *map_variable_attnos(Node *node,
 								 int target_varno, int sublevels_up,
-								 const struct AttrMap *attno_map,
+								 const AttrMap *attno_map,
 								 Oid to_rowtype, bool *found_whole_row);
 
 extern Node *ReplaceVarFromTargetList(Var *var,

src/include/storage/bufmgr.h

@@ -93,6 +93,9 @@ typedef enum ExtendBufferedFlags
 	EB_LOCK_TARGET = (1 << 5),
 }			ExtendBufferedFlags;
 
+/* forward declared, to avoid including smgr.h here */
+typedef struct SMgrRelationData *SMgrRelation;
+
 /*
  * Some functions identify relations either by relation or smgr +
  * relpersistence.  Used via the BMR_REL()/BMR_SMGR() macros below.  This
@@ -101,7 +104,7 @@ typedef enum ExtendBufferedFlags
 typedef struct BufferManagerRelation
 {
 	Relation	rel;
-	struct SMgrRelationData *smgr;
+	SMgrRelation smgr;
 	char		relpersistence;
 } BufferManagerRelation;
 
@@ -122,7 +125,7 @@ struct ReadBuffersOperation
 {
 	/* The following members should be set by the caller. */
 	Relation	rel;			/* optional */
-	struct SMgrRelationData *smgr;
+	SMgrRelation smgr;
 	char		persistence;
 	ForkNumber	forknum;
 	BufferAccessStrategy strategy;
@@ -143,11 +146,8 @@ struct ReadBuffersOperation
 
 typedef struct ReadBuffersOperation ReadBuffersOperation;
 
-/* forward declared, to avoid having to expose buf_internals.h here */
-struct WritebackContext;
-
-/* forward declared, to avoid including smgr.h here */
-struct SMgrRelationData;
+/* to avoid having to expose buf_internals.h here */
+typedef struct WritebackContext WritebackContext;
 
 /* in globals.c ... this duplicates miscadmin.h */
 extern PGDLLIMPORT int NBuffers;
@@ -201,7 +201,7 @@ extern PGDLLIMPORT int32 *LocalRefCount;
 /*
  * prototypes for functions in bufmgr.c
  */
-extern PrefetchBufferResult PrefetchSharedBuffer(struct SMgrRelationData *smgr_reln,
+extern PrefetchBufferResult PrefetchSharedBuffer(SMgrRelation smgr_reln,
 												 ForkNumber forkNum,
 												 BlockNumber blockNum);
 extern PrefetchBufferResult PrefetchBuffer(Relation reln, ForkNumber forkNum,
@@ -268,15 +268,15 @@ extern BlockNumber RelationGetNumberOfBlocksInFork(Relation relation,
 												   ForkNumber forkNum);
 extern void FlushOneBuffer(Buffer buffer);
 extern void FlushRelationBuffers(Relation rel);
-extern void FlushRelationsAllBuffers(struct SMgrRelationData **smgrs, int nrels);
+extern void FlushRelationsAllBuffers(SMgrRelation *smgrs, int nrels);
 extern void CreateAndCopyRelationData(RelFileLocator src_rlocator,
 									  RelFileLocator dst_rlocator,
 									  bool permanent);
 extern void FlushDatabaseBuffers(Oid dbid);
-extern void DropRelationBuffers(struct SMgrRelationData *smgr_reln,
+extern void DropRelationBuffers(SMgrRelation smgr_reln,
 								ForkNumber *forkNum,
 								int nforks, BlockNumber *firstDelBlock);
-extern void DropRelationsAllBuffers(struct SMgrRelationData **smgr_reln,
+extern void DropRelationsAllBuffers(SMgrRelation *smgr_reln,
 									int nlocators);
 extern void DropDatabaseBuffers(Oid dbid);
 
@@ -298,7 +298,7 @@ extern bool ConditionalLockBufferForCleanup(Buffer buffer);
 extern bool IsBufferCleanupOK(Buffer buffer);
 extern bool HoldingBufferPinThatDelaysRecovery(void);
 
-extern bool BgBufferSync(struct WritebackContext *wb_context);
+extern bool BgBufferSync(WritebackContext *wb_context);
 
 extern uint32 GetPinLimit(void);
 extern uint32 GetLocalPinLimit(void);

src/include/storage/bulk_write.h

@@ -28,10 +28,10 @@ typedef struct BulkWriteState BulkWriteState;
 typedef PGIOAlignedBlock *BulkWriteBuffer;
 
 /* forward declared from smgr.h */
-struct SMgrRelationData;
+typedef struct SMgrRelationData *SMgrRelation;
 
 extern BulkWriteState *smgr_bulk_start_rel(Relation rel, ForkNumber forknum);
-extern BulkWriteState *smgr_bulk_start_smgr(struct SMgrRelationData *smgr, ForkNumber forknum, bool use_wal);
+extern BulkWriteState *smgr_bulk_start_smgr(SMgrRelation smgr, ForkNumber forknum, bool use_wal);
 
 extern BulkWriteBuffer smgr_bulk_get_buf(BulkWriteState *bulkstate);
 extern void smgr_bulk_write(BulkWriteState *bulkstate, BlockNumber blocknum, BulkWriteBuffer buf, bool page_std);

src/include/storage/dsm.h

@@ -20,9 +20,9 @@ typedef struct dsm_segment dsm_segment;
 #define DSM_CREATE_NULL_IF_MAXSEGMENTS			0x0001
 
 /* Startup and shutdown functions. */
-struct PGShmemHeader;			/* avoid including pg_shmem.h */
+typedef struct PGShmemHeader PGShmemHeader; /* avoid including pg_shmem.h */
 extern void dsm_cleanup_using_control_segment(dsm_handle old_control_handle);
-extern void dsm_postmaster_startup(struct PGShmemHeader *);
+extern void dsm_postmaster_startup(PGShmemHeader *);
 extern void dsm_backend_shutdown(void);
 extern void dsm_detach_all(void);
 

src/include/storage/shmem.h

@@ -27,8 +27,9 @@
 
 /* shmem.c */
 extern PGDLLIMPORT slock_t *ShmemLock;
-struct PGShmemHeader;			/* avoid including storage/pg_shmem.h here */
-extern void InitShmemAccess(struct PGShmemHeader *seghdr);
+typedef struct PGShmemHeader PGShmemHeader; /* avoid including
+											 * storage/pg_shmem.h here */
+extern void InitShmemAccess(PGShmemHeader *seghdr);
 extern void InitShmemAllocation(void);
 extern void *ShmemAlloc(Size size);
 extern void *ShmemAllocNoError(Size size);

src/include/tcop/pquery.h

@@ -17,7 +17,7 @@
 #include "nodes/parsenodes.h"
 #include "utils/portal.h"
 
-struct PlannedStmt;				/* avoid including plannodes.h here */
+typedef struct PlannedStmt PlannedStmt; /* avoid including plannodes.h here */
 
 
 extern PGDLLIMPORT Portal ActivePortal;
@@ -44,7 +44,7 @@ extern uint64 PortalRunFetch(Portal portal,
 							 long count,
 							 DestReceiver *dest);
 
-extern bool PlannedStmtRequiresSnapshot(struct PlannedStmt *pstmt);
+extern bool PlannedStmtRequiresSnapshot(PlannedStmt *pstmt);
 
 extern void EnsurePortalSnapshotExists(void);
 

src/include/utils/array.h

@@ -65,8 +65,8 @@
 #include "utils/expandeddatum.h"
 
 /* avoid including execnodes.h here */
-struct ExprState;
-struct ExprContext;
+typedef struct ExprState ExprState;
+typedef struct ExprContext ExprContext;
 
 
 /*
@@ -384,7 +384,7 @@ extern ArrayType *array_set(ArrayType *array, int nSubscripts, int *indx,
 							int arraytyplen, int elmlen, bool elmbyval, char elmalign);
 
 extern Datum array_map(Datum arrayd,
-					   struct ExprState *exprstate, struct ExprContext *econtext,
+					   ExprState *exprstate, ExprContext *econtext,
 					   Oid retType, ArrayMapState *amstate);
 
 extern void array_bitmap_copy(bits8 *destbitmap, int destoffset,

src/include/utils/lsyscache.h

@@ -19,7 +19,7 @@
 #include "nodes/pg_list.h"
 
 /* avoid including subscripting.h here */
-struct SubscriptRoutines;
+typedef struct SubscriptRoutines SubscriptRoutines;
 
 /* Result list element for get_op_index_interpretation */
 typedef struct OpIndexInterpretation
@@ -187,8 +187,8 @@ extern Oid	get_typmodin(Oid typid);
 extern Oid	get_typcollation(Oid typid);
 extern bool type_is_collatable(Oid typid);
 extern RegProcedure get_typsubscript(Oid typid, Oid *typelemp);
-extern const struct SubscriptRoutines *getSubscriptingRoutines(Oid typid,
-															   Oid *typelemp);
+extern const SubscriptRoutines *getSubscriptingRoutines(Oid typid,
+														Oid *typelemp);
 extern Oid	getBaseType(Oid typid);
 extern Oid	getBaseTypeAndTypmod(Oid typid, int32 *typmod);
 extern int32 get_typavgwidth(Oid typid, int32 typmod);

src/include/utils/plancache.h

@@ -24,8 +24,8 @@
 
 
 /* Forward declarations, to avoid including parsenodes.h here */
-struct Query;
-struct RawStmt;
+typedef struct Query Query;
+typedef struct RawStmt RawStmt;
 
 /* possible values for plan_cache_mode */
 typedef enum
@@ -105,8 +105,8 @@ typedef void (*PostRewriteHook) (List *querytree_list, void *arg);
 typedef struct CachedPlanSource
 {
 	int			magic;			/* should equal CACHEDPLANSOURCE_MAGIC */
-	struct RawStmt *raw_parse_tree; /* output of raw_parser(), or NULL */
-	struct Query *analyzed_parse_tree;	/* analyzed parse tree, or NULL */
+	RawStmt    *raw_parse_tree; /* output of raw_parser(), or NULL */
+	Query	   *analyzed_parse_tree;	/* analyzed parse tree, or NULL */
 	const char *query_string;	/* source text of query */
 	CommandTag	commandTag;		/* command tag for query */
 	Oid		   *param_types;	/* array of parameter type OIDs, or NULL */
@@ -202,13 +202,13 @@ extern void ResetPlanCache(void);
 
 extern void ReleaseAllPlanCacheRefsInOwner(ResourceOwner owner);
 
-extern CachedPlanSource *CreateCachedPlan(struct RawStmt *raw_parse_tree,
+extern CachedPlanSource *CreateCachedPlan(RawStmt *raw_parse_tree,
 										  const char *query_string,
 										  CommandTag commandTag);
-extern CachedPlanSource *CreateCachedPlanForQuery(struct Query *analyzed_parse_tree,
+extern CachedPlanSource *CreateCachedPlanForQuery(Query *analyzed_parse_tree,
 												  const char *query_string,
 												  CommandTag commandTag);
-extern CachedPlanSource *CreateOneShotCachedPlan(struct RawStmt *raw_parse_tree,
+extern CachedPlanSource *CreateOneShotCachedPlan(RawStmt *raw_parse_tree,
 												 const char *query_string,
 												 CommandTag commandTag);
 extern void CompleteCachedPlan(CachedPlanSource *plansource,

src/include/utils/ruleutils.h

@@ -17,8 +17,8 @@
 #include "nodes/parsenodes.h"
 #include "nodes/pg_list.h"
 
-struct Plan;					/* avoid including plannodes.h here */
-struct PlannedStmt;
+typedef struct Plan Plan;		/* avoid including plannodes.h here */
+typedef struct PlannedStmt PlannedStmt;
 
 /* Flags for pg_get_indexdef_columns_extended() */
 #define RULE_INDEXDEF_PRETTY		0x01
@@ -37,10 +37,10 @@ extern char *pg_get_constraintdef_command(Oid constraintId);
 extern char *deparse_expression(Node *expr, List *dpcontext,
 								bool forceprefix, bool showimplicit);
 extern List *deparse_context_for(const char *aliasname, Oid relid);
-extern List *deparse_context_for_plan_tree(struct PlannedStmt *pstmt,
+extern List *deparse_context_for_plan_tree(PlannedStmt *pstmt,
 										   List *rtable_names);
 extern List *set_deparse_context_plan(List *dpcontext,
-									  struct Plan *plan, List *ancestors);
+									  Plan *plan, List *ancestors);
 extern List *select_rtable_names_for_explain(List *rtable,
 											 Bitmapset *rels_used);
 extern char *get_window_frame_options_for_explain(int frameOptions,