From 295e87660aa2616913ac8b930b7892e4c20d1cf0 Mon Sep 17 00:00:00 2001
From: be5invis <belleve@typeof.net>
Date: Thu, 20 Aug 2020 08:39:55 -0700
Subject: [PATCH] Fix slab crash when building (#671).

---
 font-src/glyphs/letter/latin.ptl | 2 ++
 font-src/support/glyph.js        | 4 +++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/font-src/glyphs/letter/latin.ptl b/font-src/glyphs/letter/latin.ptl
index 41ed94762..c52693a9a 100644
--- a/font-src/glyphs/letter/latin.ptl
+++ b/font-src/glyphs/letter/latin.ptl
@@ -3780,8 +3780,10 @@ glyph-block Letter-Latin-Lower-N : begin
 
 	define [NTopLeftSerif] : begin
 		tagged 'serifLT' : LeftwardTopSerif SB XH SideJut
+		glyph-proc
 	define [NBottomLeftSerif] : if (!para.isItalic)
 		tagged 'serifLB' : CenterBottomSerif (SB + HalfStroke * HVContrast) 0 Jut
+		glyph-proc
 	define [NBottomRightSerif] : if (para.isItalic)
 		tagged 'serifRB' : RightwardBottomSerif RightSB 0 SideJut
 		tagged 'serifRB' : CenterBottomSerif (RightSB - HalfStroke * HVContrast) 0 Jut
diff --git a/font-src/support/glyph.js b/font-src/support/glyph.js
index 54fbb083a..5ffd9414f 100644
--- a/font-src/support/glyph.js
+++ b/font-src/support/glyph.js
@@ -54,7 +54,9 @@ module.exports = class Glyph {
 	}
 	// Inclusion
 	include(component, copyAnchors, copyWidth) {
-		if (component instanceof Function) {
+		if (!component) {
+			throw new Error("Unreachable: Attempt to include a Null or Undefined");
+		} else if (component instanceof Function) {
 			const t = this.defaultTag;
 			if (component.tag) this.defaultTag = component.tag;
 			component.call(this, copyAnchors, copyWidth);