Index: src/AST/Type.hpp
===================================================================
--- src/AST/Type.hpp	(revision 68ff3de6e19eb721d9358d17fa972de80caa1eae)
+++ src/AST/Type.hpp	(revision a804f81298e916805241c4eb6b0be21bac7c648e)
@@ -402,8 +402,8 @@
 
 	// compact representation used for map lookups.
-	struct TypeEnvKey { 
-		const TypeDecl * base;
-		int formal_usage;
-		int expr_id;
+	struct TypeEnvKey {
+		const TypeDecl * base = nullptr;
+		int formal_usage = 0;
+		int expr_id = 0;
 
 		TypeEnvKey() = default;
@@ -440,6 +440,6 @@
 	const Type * accept( Visitor & v ) const override { return v.visit( this ); }
 
-	std::string typeString() const { 
-		if (formal_usage > 0) return std::string("_") + std::to_string(formal_usage) + "_" + std::to_string(expr_id) + "_" + name; 
+	std::string typeString() const {
+		if (formal_usage > 0) return std::string("_") + std::to_string(formal_usage) + "_" + std::to_string(expr_id) + "_" + name;
 		else return name;
 	}
@@ -548,5 +548,5 @@
 			res = p * res + x.expr_id;
 			return res;
-		} 
+		}
 	};
 }