Remove useless assertions

We don't need Assert(IsA(foo, String)) right before running
strVal(foo), since strVal() already does the assertion internally (via
castNode()).

Author: petere

src/backend/commands/tablecmds.c

@@ -8271,7 +8271,6 @@ ATExecSetStorage(Relation rel, const char *colName, Node *newValue, LOCKMODE loc
 	AttrNumber	attnum;
 	ObjectAddress address;
 
-	Assert(IsA(newValue, String));
 	storagemode = strVal(newValue);
 
 	if (pg_strcasecmp(storagemode, "plain") == 0)
@@ -16171,7 +16170,6 @@ ATExecSetCompression(AlteredTableInfo *tab,
 	char		cmethod;
 	ObjectAddress address;
 
-	Assert(IsA(newValue, String));
 	compression = strVal(newValue);
 
 	attrel = table_open(AttributeRelationId, RowExclusiveLock);

src/backend/commands/typecmds.c

@@ -3577,7 +3577,6 @@ replace_domain_constraint_value(ParseState *pstate, ColumnRef *cref)
 		Node	   *field1 = (Node *) linitial(cref->fields);
 		char	   *colname;
 
-		Assert(IsA(field1, String));
 		colname = strVal(field1);
 		if (strcmp(colname, "value") == 0)
 		{

src/backend/executor/functions.c

@@ -318,12 +318,10 @@ sql_fn_post_column_ref(ParseState *pstate, ColumnRef *cref, Node *var)
 		nnames--;
 
 	field1 = (Node *) linitial(cref->fields);
-	Assert(IsA(field1, String));
 	name1 = strVal(field1);
 	if (nnames > 1)
 	{
 		subfield = (Node *) lsecond(cref->fields);
-		Assert(IsA(subfield, String));
 		name2 = strVal(subfield);
 	}
 

src/backend/parser/parse_expr.c

@@ -631,7 +631,6 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref)
 			{
 				Node	   *field1 = (Node *) linitial(cref->fields);
 
-				Assert(IsA(field1, String));
 				colname = strVal(field1);
 
 				/* Try to identify as an unqualified column */
@@ -664,7 +663,6 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref)
 				Node	   *field1 = (Node *) linitial(cref->fields);
 				Node	   *field2 = (Node *) lsecond(cref->fields);
 
-				Assert(IsA(field1, String));
 				relname = strVal(field1);
 
 				/* Locate the referenced nsitem */
@@ -685,7 +683,6 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref)
 					break;
 				}
 
-				Assert(IsA(field2, String));
 				colname = strVal(field2);
 
 				/* Try to identify as a column of the nsitem */
@@ -712,9 +709,7 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref)
 				Node	   *field2 = (Node *) lsecond(cref->fields);
 				Node	   *field3 = (Node *) lthird(cref->fields);
 
-				Assert(IsA(field1, String));
 				nspname = strVal(field1);
-				Assert(IsA(field2, String));
 				relname = strVal(field2);
 
 				/* Locate the referenced nsitem */
@@ -735,7 +730,6 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref)
 					break;
 				}
 
-				Assert(IsA(field3, String));
 				colname = strVal(field3);
 
 				/* Try to identify as a column of the nsitem */
@@ -764,11 +758,8 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref)
 				Node	   *field4 = (Node *) lfourth(cref->fields);
 				char	   *catname;
 
-				Assert(IsA(field1, String));
 				catname = strVal(field1);
-				Assert(IsA(field2, String));
 				nspname = strVal(field2);
-				Assert(IsA(field3, String));
 				relname = strVal(field3);
 
 				/*
@@ -798,7 +789,6 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref)
 					break;
 				}
 
-				Assert(IsA(field4, String));
 				colname = strVal(field4);
 
 				/* Try to identify as a column of the nsitem */

src/pl/plpgsql/src/pl_comp.c

@@ -1213,7 +1213,6 @@ resolve_column_ref(ParseState *pstate, PLpgSQL_expr *expr,
 			{
 				Node	   *field1 = (Node *) linitial(cref->fields);
 
-				Assert(IsA(field1, String));
 				name1 = strVal(field1);
 				nnames_scalar = 1;
 				nnames_wholerow = 1;
@@ -1224,7 +1223,6 @@ resolve_column_ref(ParseState *pstate, PLpgSQL_expr *expr,
 				Node	   *field1 = (Node *) linitial(cref->fields);
 				Node	   *field2 = (Node *) lsecond(cref->fields);
 
-				Assert(IsA(field1, String));
 				name1 = strVal(field1);
 
 				/* Whole-row reference? */
@@ -1236,7 +1234,6 @@ resolve_column_ref(ParseState *pstate, PLpgSQL_expr *expr,
 					break;
 				}
 
-				Assert(IsA(field2, String));
 				name2 = strVal(field2);
 				colname = name2;
 				nnames_scalar = 2;
@@ -1250,9 +1247,7 @@ resolve_column_ref(ParseState *pstate, PLpgSQL_expr *expr,
 				Node	   *field2 = (Node *) lsecond(cref->fields);
 				Node	   *field3 = (Node *) lthird(cref->fields);
 
-				Assert(IsA(field1, String));
 				name1 = strVal(field1);
-				Assert(IsA(field2, String));
 				name2 = strVal(field2);
 
 				/* Whole-row reference? */
@@ -1264,7 +1259,6 @@ resolve_column_ref(ParseState *pstate, PLpgSQL_expr *expr,
 					break;
 				}
 
-				Assert(IsA(field3, String));
 				name3 = strVal(field3);
 				colname = name3;
 				nnames_field = 2;