From ef616e43a4dccc88d02e793db3c86b1a10b3e029 Mon Sep 17 00:00:00 2001
From: g-w1 <jacoblevgw@gmail.com>
Date: Wed, 23 Dec 2020 22:24:24 -0500
Subject: [PATCH] try to list all not handled errors but blocking on #7218,
 NOTE: this will fail the ci

---
 src/zir_sema.zig | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/src/zir_sema.zig b/src/zir_sema.zig
index c4f3e891a369..a44ea5e93e3a 100644
--- a/src/zir_sema.zig
+++ b/src/zir_sema.zig
@@ -1412,9 +1412,8 @@ fn validateSwitch(mod: *Module, scope: *Scope, target: *Inst, inst: *zir.Inst.Sw
             const gotten_err_set = target.ty.getErrs();
             const is_anyerror = gotten_err_set == .anyerror;
             var is_single = gotten_err_set == .err_single;
-            if (is_anyerror and !(inst.kw_args.special_prong == .@"else")) {
+            if (is_anyerror and !(inst.kw_args.special_prong == .@"else"))
                 return mod.fail(scope, inst.base.src, "else prong required when switching on type 'anyerror'", .{});
-            }
             var seen_values = std.HashMap(Value, usize, Value.hash, Value.eql, std.hash_map.DefaultMaxLoadPercentage).init(mod.gpa);
             defer seen_values.deinit();
             for (inst.positionals.items) |item| {
@@ -1437,8 +1436,22 @@ fn validateSwitch(mod: *Module, scope: *Scope, target: *Inst, inst: *zir.Inst.Sw
                 //     }
                 // }
             }
-            if (!is_single and !is_anyerror and gotten_err_set.multiple.size > inst.positionals.items.len and !(inst.kw_args.special_prong == .@"else"))
-                return mod.fail(scope, inst.base.src, "switch must handle all possibilities", .{});
+            if (!is_single and !is_anyerror and gotten_err_set.multiple.size > inst.positionals.items.len and !(inst.kw_args.special_prong == .@"else")) {
+                var not_handled = false;
+                var it = gotten_err_set.multiple.iterator();
+                while (it.next()) |entry| {
+                    var err: Value.Payload.Error = .{ .name = entry.key, .value = entry.value };
+                    const e_val = Value.initPayload(&err.base);
+                    if (seen_values.get(e_val) == null) {
+                        switch (mod.fail(scope, inst.base.src, "error.{} not handled in switch", .{entry.key})) {
+                            error.AnalysisFail => {},
+                            else => |e| return e,
+                        }
+                        not_handled = true;
+                    }
+                }
+                if (not_handled) return error.AnalysisFail;
+            }
         },
         .Int, .ComptimeInt => {
             var range_set = @import("RangeSet.zig").init(mod.gpa);