From 8503eff8c12697c35ab5c73d6651c4b996339706 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <superjoe30@gmail.com>
Date: Sun, 22 Apr 2018 23:46:55 -0400
Subject: [PATCH] add compile error for invalid deref on switch target

closes #945
---
 src/ir.cpp              |  5 ++++-
 test/compile_errors.zig | 15 +++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/src/ir.cpp b/src/ir.cpp
index 865a6823be..cd00fc6230 100644
--- a/src/ir.cpp
+++ b/src/ir.cpp
@@ -14782,7 +14782,10 @@ static TypeTableEntry *ir_analyze_instruction_switch_target(IrAnalyze *ira,
         return out_val->type;
     }
 
-    assert(target_value_ptr->value.type->id == TypeTableEntryIdPointer);
+    if (target_value_ptr->value.type->id != TypeTableEntryIdPointer) {
+        ir_add_error(ira, target_value_ptr, buf_sprintf("invalid deref on switch target"));
+        return ira->codegen->builtin_types.entry_invalid;
+    }
 
     TypeTableEntry *target_type = target_value_ptr->value.type->data.pointer.child_type;
     ConstExprValue *pointee_val = nullptr;
diff --git a/test/compile_errors.zig b/test/compile_errors.zig
index 2c4e35c562..f8febc27b8 100644
--- a/test/compile_errors.zig
+++ b/test/compile_errors.zig
@@ -1,6 +1,21 @@
 const tests = @import("tests.zig");
 
 pub fn addCases(cases: &tests.CompileErrorContext) void {
+    cases.add("invalid deref on switch target",
+        \\comptime {
+        \\    var tile = Tile.Empty;
+        \\    switch (*tile) {
+        \\        Tile.Empty => {},
+        \\        Tile.Filled => {},
+        \\    }
+        \\}
+        \\const Tile = enum {
+        \\    Empty,
+        \\    Filled,
+        \\};
+    ,
+        ".tmp_source.zig:3:13: error: invalid deref on switch target");
+
     cases.add("invalid field access in comptime",
         \\comptime { var x = doesnt_exist.whatever; }
     ,