From 882ff042e24eeaf5f6a50ebf0ad270158b3ecb25 Mon Sep 17 00:00:00 2001
From: jaina heartles <me@heartles.xyz>
Date: Sat, 10 Dec 2022 01:26:44 -0800
Subject: [PATCH] Template compilation errors on bad switch

---
 src/template/lib.zig | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/template/lib.zig b/src/template/lib.zig
index 7f02a20..33b55d3 100644
--- a/src/template/lib.zig
+++ b/src/template/lib.zig
@@ -130,6 +130,11 @@ fn executeStatement(
         .@"switch" => |switch_stmt| {
             const expr = evaluateExpression(switch_stmt.expression, args, captures, context);
 
+            const exhaustive = switch_stmt.cases.len == std.meta.fields(@TypeOf(expr)).len;
+
+            if (exhaustive and switch_stmt.else_branch != null) @compileError("Unused else branch in switch");
+            if (!exhaustive and switch_stmt.else_branch == null) @compileError("Not all switch cases covered");
+
             var found = false;
             inline for (switch_stmt.cases) |case| {
                 if (std.meta.isTag(expr, case.header.tag)) {