diff --git a/src/fontcache.cpp b/src/fontcache.cpp
--- a/src/fontcache.cpp
+++ b/src/fontcache.cpp
@@ -41,7 +41,7 @@ FontCache::FontCache(FontSize fs) : pare
 		ascender(_default_font_ascender[fs]), descender(_default_font_ascender[fs] - _default_font_height[fs]),
 		units_per_em(1)
 {
-	assert(parent == NULL || this->fs == parent->fs);
+	assert(this->parent == NULL || this->fs == this->parent->fs);
 	FontCache::caches[this->fs] = this;
 	Layouter::ResetFontCache(this->fs);
 }
@@ -49,7 +49,7 @@ FontCache::FontCache(FontSize fs) : pare
 /** Clean everything up. */
 FontCache::~FontCache()
 {
-	assert(this->fs == parent->fs);
+	assert(this->fs == this->parent->fs);
 	FontCache::caches[this->fs] = this->parent;
 	Layouter::ResetFontCache(this->fs);
 }
@@ -474,7 +474,7 @@ static bool GetFontAAState(FontSize size
 
 const Sprite *FreeTypeFontCache::GetGlyph(GlyphID key)
 {
-	if ((key & SPRITE_GLYPH) != 0) return parent->GetGlyph(key);
+	if ((key & SPRITE_GLYPH) != 0) return this->parent->GetGlyph(key);
 
 	/* Check for the glyph in our cache */
 	GlyphEntry *glyph = this->GetGlyphPtr(key);