1 files changed, 59 insertions, 0 deletions
diff --git a/src/backend/nodes/nodeFuncs.c b/src/backend/nodes/nodeFuncs.c
index a896d763b8f..908f397d501 100644
--- a/src/backend/nodes/nodeFuncs.c
+++ b/src/backend/nodes/nodeFuncs.c
@@ -572,6 +572,65 @@ relabel_to_typmod(Node *expr, int32 typmod)
 }
 
 /*
+ * 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.
  *