diff --git a/src/ld-canvas.c b/src/ld-canvas.c
index dcab249..07d7a51 100644
--- a/src/ld-canvas.c
+++ b/src/ld-canvas.c
@@ -384,6 +384,9 @@ ld_canvas_new (void)
 void
 ld_canvas_set_document (LdCanvas *self, LdDocument *document)
 {
+	g_return_if_fail (LD_IS_CANVAS (self));
+	g_return_if_fail (LD_IS_DOCUMENT (document));
+
 	if (self->priv->document)
 		g_object_unref (self->priv->document);
 
@@ -403,6 +406,7 @@ ld_canvas_set_document (LdCanvas *self, LdDocument *document)
 LdDocument *
 ld_canvas_get_document (LdCanvas *self)
 {
+	g_return_val_if_fail (LD_IS_CANVAS (self), NULL);
 	return self->priv->document;
 }
 
@@ -416,6 +420,9 @@ ld_canvas_get_document (LdCanvas *self)
 void
 ld_canvas_set_library (LdCanvas *self, LdLibrary *library)
 {
+	g_return_if_fail (LD_IS_CANVAS (self));
+	g_return_if_fail (LD_IS_LIBRARY (library));
+
 	if (self->priv->library)
 		g_object_unref (self->priv->library);
 
@@ -435,6 +442,7 @@ ld_canvas_set_library (LdCanvas *self, LdLibrary *library)
 LdLibrary *
 ld_canvas_get_library (LdCanvas *self)
 {
+	g_return_val_if_fail (LD_IS_CANVAS (self), NULL);
 	return self->priv->library;
 }
 
diff --git a/src/ld-library.c b/src/ld-library.c
index 2bd0365..4c980d0 100644
--- a/src/ld-library.c
+++ b/src/ld-library.c
@@ -43,11 +43,10 @@ struct _LdLibraryPrivate
 
 G_DEFINE_TYPE (LdLibrary, ld_library, G_TYPE_OBJECT);
 
-static void
-ld_library_finalize (GObject *gobject);
+static void ld_library_finalize (GObject *gobject);
 
-static LdSymbolCategory *load_category
-	(LdLibrary *self, const char *path, const char *name);
+static LdSymbolCategory *load_category (LdLibrary *self,
+	const gchar *path, const gchar *name);
 static gboolean load_category_cb (const gchar *base,
 	const gchar *filename, gpointer userdata);
 static void load_category_symbol_cb (LdSymbol *symbol, gpointer user_data);
@@ -175,7 +174,7 @@ LoadCategoryData;
  * Loads a category into the library.
  */
 static LdSymbolCategory *
-load_category (LdLibrary *self, const char *path, const char *name)
+load_category (LdLibrary *self, const gchar *path, const gchar *name)
 {
 	LdSymbolCategory *cat;
 	gchar *icon_file, *category_file;
@@ -353,16 +352,16 @@ LibraryLoadData;
  * Load the contents of a directory into the library.
  */
 gboolean
-ld_library_load (LdLibrary *self, const char *path)
+ld_library_load (LdLibrary *self, const gchar *directory)
 {
 	LibraryLoadData data;
 
 	g_return_val_if_fail (LD_IS_LIBRARY (self), FALSE);
-	g_return_val_if_fail (path != NULL, FALSE);
+	g_return_val_if_fail (directory != NULL, FALSE);
 
 	data.self = self;
 	data.changed = FALSE;
-	foreach_dir (path, ld_library_load_cb, &data, NULL);
+	foreach_dir (directory, ld_library_load_cb, &data, NULL);
 
 	if (data.changed)
 		g_signal_emit (self, LD_LIBRARY_GET_CLASS (self)->changed_signal, 0);
@@ -379,7 +378,6 @@ static gboolean
 ld_library_load_cb (const gchar *base, const gchar *filename, gpointer userdata)
 {
 	LdSymbolCategory *cat;
-	gchar *categ_path;
 	LibraryLoadData *data;
 
 	g_return_val_if_fail (base != NULL, FALSE);
diff --git a/src/ld-lua.c b/src/ld-lua.c
index 4ed68eb..f51ab1c 100644
--- a/src/ld-lua.c
+++ b/src/ld-lua.c
@@ -223,6 +223,8 @@ gboolean
 ld_lua_check_file (LdLua *self, const gchar *filename)
 {
 	g_return_val_if_fail (LD_IS_LUA (self), FALSE);
+	g_return_val_if_fail (filename != NULL, FALSE);
+
 	return g_str_has_suffix (filename, ".lua")
 		&& g_file_test (filename, G_FILE_TEST_IS_REGULAR);
 }
@@ -297,6 +299,7 @@ ld_lua_private_draw (LdLua *self, LdLuaSymbol *symbol, cairo_t *cr)
 
 	g_return_if_fail (LD_IS_LUA (self));
 	g_return_if_fail (LD_IS_LUA_SYMBOL (symbol));
+	g_return_if_fail (cr != NULL);
 
 	data.symbol = symbol;
 	data.cr = cr;
diff --git a/src/ld-symbol-category.c b/src/ld-symbol-category.c
index 9c74e90..b7963aa 100644
--- a/src/ld-symbol-category.c
+++ b/src/ld-symbol-category.c
@@ -49,16 +49,11 @@ enum
 	PROP_IMAGE_PATH
 };
 
-static void
-ld_symbol_category_get_property (GObject *object, guint property_id,
+static void ld_symbol_category_get_property (GObject *object, guint property_id,
 	GValue *value, GParamSpec *pspec);
-
-static void
-ld_symbol_category_set_property (GObject *object, guint property_id,
+static void ld_symbol_category_set_property (GObject *object, guint property_id,
 	const GValue *value, GParamSpec *pspec);
-
-static void
-ld_symbol_category_finalize (GObject *gobject);
+static void ld_symbol_category_finalize (GObject *gobject);
 
 
 static void
@@ -179,6 +174,7 @@ ld_symbol_category_finalize (GObject *gobject)
 	G_OBJECT_CLASS (ld_symbol_category_parent_class)->finalize (gobject);
 }
 
+
 /**
  * ld_symbol_category_new:
  * @name: The name of the new category.
@@ -235,7 +231,7 @@ ld_symbol_category_get_name (LdSymbolCategory *self)
 /**
  * ld_symbol_category_set_human_name:
  * @self: An #LdSymbolCategory object.
- * @name: The new localized human name for this category.
+ * @human_name: The new localized human name for this category.
  */
 void
 ld_symbol_category_set_human_name (LdSymbolCategory *self,
diff --git a/src/ld-symbol.c b/src/ld-symbol.c
index 6005776..014016e 100644
--- a/src/ld-symbol.c
+++ b/src/ld-symbol.c
@@ -90,7 +90,6 @@ enum
 
 static void ld_symbol_get_property (GObject *object, guint property_id,
 	GValue *value, GParamSpec *pspec);
-
 static void ld_symbol_set_property (GObject *object, guint property_id,
 	const GValue *value, GParamSpec *pspec);
 
diff --git a/src/logdiag.c b/src/logdiag.c
index 324180a..9752978 100644
--- a/src/logdiag.c
+++ b/src/logdiag.c
@@ -15,7 +15,8 @@
 #include "ld-window-main.h"
 
 
-int main (int argc, char *argv[])
+int
+main (int argc, char *argv[])
 {
 	GtkWidget *wnd;