Move strip_implicit_coercions() from optimizer to nodeFuncs.c.

Use of this function has spread into the parser and rewriter, so it seems
like time to pull it out of the optimizer and put it into the more central
nodeFuncs module.  This eliminates the need to #include optimizer/clauses.h
in most of the calling files, demonstrating that this function was indeed a
bit outside the normal code reference patterns.

Author: tglsfdc

src/backend/nodes/nodeFuncs.c

@@ -571,6 +571,65 @@ relabel_to_typmod(Node *expr, int32 typmod)
 									COERCE_EXPLICIT_CAST);
 }
 
+/*
+ * strip_implicit_coercions: remove implicit coercions at top level of tree
+ *
+ * This doesn't modify or copy the input expression tree, just return a
+ * pointer to a suitable place within it.
+ *
+ * Note: there isn't any useful thing we can do with a RowExpr here, so
+ * just return it unchanged, even if it's marked as an implicit coercion.
+ */
+Node *
+strip_implicit_coercions(Node *node)
+{
+	if (node == NULL)
+		return NULL;
+	if (IsA(node, FuncExpr))
+	{
+		FuncExpr   *f = (FuncExpr *) node;
+
+		if (f->funcformat == COERCE_IMPLICIT_CAST)
+			return strip_implicit_coercions(linitial(f->args));
+	}
+	else if (IsA(node, RelabelType))
+	{
+		RelabelType *r = (RelabelType *) node;
+
+		if (r->relabelformat == COERCE_IMPLICIT_CAST)
+			return strip_implicit_coercions((Node *) r->arg);
+	}
+	else if (IsA(node, CoerceViaIO))
+	{
+		CoerceViaIO *c = (CoerceViaIO *) node;
+
+		if (c->coerceformat == COERCE_IMPLICIT_CAST)
+			return strip_implicit_coercions((Node *) c->arg);
+	}
+	else if (IsA(node, ArrayCoerceExpr))
+	{
+		ArrayCoerceExpr *c = (ArrayCoerceExpr *) node;
+
+		if (c->coerceformat == COERCE_IMPLICIT_CAST)
+			return strip_implicit_coercions((Node *) c->arg);
+	}
+	else if (IsA(node, ConvertRowtypeExpr))
+	{
+		ConvertRowtypeExpr *c = (ConvertRowtypeExpr *) node;
+
+		if (c->convertformat == COERCE_IMPLICIT_CAST)
+			return strip_implicit_coercions((Node *) c->arg);
+	}
+	else if (IsA(node, CoerceToDomain))
+	{
+		CoerceToDomain *c = (CoerceToDomain *) node;
+
+		if (c->coercionformat == COERCE_IMPLICIT_CAST)
+			return strip_implicit_coercions((Node *) c->arg);
+	}
+	return node;
+}
+
 /*
  * expression_returns_set
  *	  Test whether an expression returns a set result.

src/backend/optimizer/util/clauses.c

@@ -2070,62 +2070,6 @@ CommuteRowCompareExpr(RowCompareExpr *clause)
 	clause->rargs = temp;
 }
 
-/*
- * strip_implicit_coercions: remove implicit coercions at top level of tree
- *
- * Note: there isn't any useful thing we can do with a RowExpr here, so
- * just return it unchanged, even if it's marked as an implicit coercion.
- */
-Node *
-strip_implicit_coercions(Node *node)
-{
-	if (node == NULL)
-		return NULL;
-	if (IsA(node, FuncExpr))
-	{
-		FuncExpr   *f = (FuncExpr *) node;
-
-		if (f->funcformat == COERCE_IMPLICIT_CAST)
-			return strip_implicit_coercions(linitial(f->args));
-	}
-	else if (IsA(node, RelabelType))
-	{
-		RelabelType *r = (RelabelType *) node;
-
-		if (r->relabelformat == COERCE_IMPLICIT_CAST)
-			return strip_implicit_coercions((Node *) r->arg);
-	}
-	else if (IsA(node, CoerceViaIO))
-	{
-		CoerceViaIO *c = (CoerceViaIO *) node;
-
-		if (c->coerceformat == COERCE_IMPLICIT_CAST)
-			return strip_implicit_coercions((Node *) c->arg);
-	}
-	else if (IsA(node, ArrayCoerceExpr))
-	{
-		ArrayCoerceExpr *c = (ArrayCoerceExpr *) node;
-
-		if (c->coerceformat == COERCE_IMPLICIT_CAST)
-			return strip_implicit_coercions((Node *) c->arg);
-	}
-	else if (IsA(node, ConvertRowtypeExpr))
-	{
-		ConvertRowtypeExpr *c = (ConvertRowtypeExpr *) node;
-
-		if (c->convertformat == COERCE_IMPLICIT_CAST)
-			return strip_implicit_coercions((Node *) c->arg);
-	}
-	else if (IsA(node, CoerceToDomain))
-	{
-		CoerceToDomain *c = (CoerceToDomain *) node;
-
-		if (c->coercionformat == COERCE_IMPLICIT_CAST)
-			return strip_implicit_coercions((Node *) c->arg);
-	}
-	return node;
-}
-
 /*
  * Helper for eval_const_expressions: check that datatype of an attribute
  * is still what it was when the expression was parsed.  This is needed to

src/backend/parser/parse_clause.c

@@ -21,7 +21,6 @@
 #include "commands/defrem.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
-#include "optimizer/clauses.h"
 #include "optimizer/tlist.h"
 #include "parser/analyze.h"
 #include "parser/parsetree.h"

src/backend/parser/parse_relation.c

@@ -24,7 +24,6 @@
 #include "funcapi.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
-#include "optimizer/clauses.h"
 #include "parser/parsetree.h"
 #include "parser/parse_relation.h"
 #include "parser/parse_type.h"

src/backend/rewrite/rewriteHandler.c

@@ -19,7 +19,6 @@
 #include "foreign/fdwapi.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
-#include "optimizer/clauses.h"
 #include "parser/analyze.h"
 #include "parser/parse_coerce.h"
 #include "parser/parsetree.h"

src/backend/utils/adt/ruleutils.c

@@ -38,7 +38,6 @@
 #include "funcapi.h"
 #include "nodes/makefuncs.h"
 #include "nodes/nodeFuncs.h"
-#include "optimizer/clauses.h"
 #include "optimizer/tlist.h"
 #include "parser/keywords.h"
 #include "parser/parse_func.h"

src/include/nodes/nodeFuncs.h

@@ -30,6 +30,7 @@ extern Oid	exprType(const Node *expr);
 extern int32 exprTypmod(const Node *expr);
 extern bool exprIsLengthCoercion(const Node *expr, int32 *coercedTypmod);
 extern Node *relabel_to_typmod(Node *expr, int32 typmod);
+extern Node *strip_implicit_coercions(Node *node);
 extern bool expression_returns_set(Node *clause);
 
 extern Oid	exprCollation(const Node *expr);

src/include/optimizer/clauses.h

@@ -77,8 +77,6 @@ extern int	NumRelids(Node *clause);
 extern void CommuteOpExpr(OpExpr *clause);
 extern void CommuteRowCompareExpr(RowCompareExpr *clause);
 
-extern Node *strip_implicit_coercions(Node *node);
-
 extern Node *eval_const_expressions(PlannerInfo *root, Node *node);
 
 extern Node *estimate_expression_value(PlannerInfo *root, Node *node);