From c2e66d9bab396a69514ec7c3c41fb0404e542f21 Mon Sep 17 00:00:00 2001
From: Andrew Kelley <andrew@ziglang.org>
Date: Wed, 7 Jul 2021 20:47:21 -0700
Subject: stage2: basic inferred error set support

 * Inferred error sets are stored in the return Type of the function,
   owned by the Module.Fn. So it cleans up that memory in deinit().
 * Sema: update the inferred error set in zirRetErrValue
   - Update relevant code in wrapErrorUnion
 * C backend: improve some some instructions to take advantage of
   liveness analysis to avoid being emitted when unused.
 * C backend: when an error union has a payload type with no runtime
   bits, emit the error union as the same type as the error set.
---
 src/Module.zig | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

(limited to 'src/Module.zig')

diff --git a/src/Module.zig b/src/Module.zig
index c48440ccc2..8ae184a377 100644
--- a/src/Module.zig
+++ b/src/Module.zig
@@ -777,8 +777,19 @@ pub const Fn = struct {
     }
 
     pub fn deinit(func: *Fn, gpa: *Allocator) void {
-        _ = func;
-        _ = gpa;
+        if (func.getInferredErrorSet()) |map| {
+            map.deinit(gpa);
+        }
+    }
+
+    pub fn getInferredErrorSet(func: *Fn) ?*std.StringHashMapUnmanaged(void) {
+        const ret_ty = func.owner_decl.ty.fnReturnType();
+        if (ret_ty.zigTypeTag() == .ErrorUnion) {
+            if (ret_ty.errorUnionSet().castTag(.error_set_inferred)) |payload| {
+                return &payload.data.map;
+            }
+        }
+        return null;
     }
 };
 
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