diff --git a/b2/Makefile b/b2/Makefile
index 0dddc0f..8325655 100644
--- a/b2/Makefile
+++ b/b2/Makefile
@@ -11,7 +11,7 @@
 
 SHELL = /bin/bash
 
-CFLAGS = -g -Wall -Wextra $(shell pkg-config --cflags glib-2.0)
+CFLAGS = -g -Wall -Wextra -Wshadow $(shell pkg-config --cflags glib-2.0)
 SLOPPY = -Wno-unused -Wno-implicit-function-declaration
 OBJS = bom.o boom.o chr.o comp.o db.o dump.o eval.o param.o relop.o \
        subex.o subst.o util.o \
diff --git a/b2/db.c b/b2/db.c
index cb08bb3..f431d3e 100644
--- a/b2/db.c
+++ b/b2/db.c
@@ -158,10 +158,10 @@ void part_finalize(struct part *part, const struct action *act)
 }
 
 
-void part_add_stock(struct part *part, struct stock *stock)
+void part_add_stock(struct part *part, struct stock *s)
 {
 	if (!part->stock) {
-		part->stock = stock;
+		part->stock = s;
 		return;
 	}
 	yyerrorf("part %s %s already has stock", part->domain, part->name);
diff --git a/b2/db.h b/b2/db.h
index b851895..509d613 100644
--- a/b2/db.h
+++ b/b2/db.h
@@ -96,7 +96,7 @@ struct part *part_lookup(const char *domain, const char *name);
 struct part *part_add(const char *domain, const char *name);
 void part_alias(struct part *a, struct part *b);
 void part_finalize(struct part *part, const struct action *act);
-void part_add_stock(struct part *part, struct stock *stock);
+void part_add_stock(struct part *part, struct stock *s);
 void part_dump(FILE *file, const struct part *part);
 
 const struct currency *currency_lookup(const char *name);