From f14cf13ff8553030c47748a0cbd455514cd1f4a3 Mon Sep 17 00:00:00 2001
From: Wooster <wooster0@proton.me>
Date: Sun, 30 Jul 2023 11:10:41 +0200
Subject: [PATCH] Sema: suggest using try/catch/if on method call on error
 union

---
 src/Sema.zig                                  |  3 +++
 .../method_call_on_error_union.zig            | 21 +++++++++++++++++++
 2 files changed, 24 insertions(+)
 create mode 100644 test/cases/compile_errors/method_call_on_error_union.zig

diff --git a/src/Sema.zig b/src/Sema.zig
index c55531d924..a5c5f37e4c 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -27888,6 +27888,9 @@ fn fieldCallBind(
             const decl = mod.declPtr(decl_idx);
             try mod.errNoteNonLazy(decl.srcLoc(mod), msg, "'{}' is not a member function", .{field_name.fmt(ip)});
         }
+        if (concrete_ty.zigTypeTag(mod) == .ErrorUnion) {
+            try sema.errNote(block, src, msg, "consider using 'try', 'catch', or 'if'", .{});
+        }
         break :msg msg;
     };
     return sema.failWithOwnedErrorMsg(block, msg);
diff --git a/test/cases/compile_errors/method_call_on_error_union.zig b/test/cases/compile_errors/method_call_on_error_union.zig
new file mode 100644
index 0000000000..4ce6b3baa8
--- /dev/null
+++ b/test/cases/compile_errors/method_call_on_error_union.zig
@@ -0,0 +1,21 @@
+const X = struct {
+    fn init() !X {
+        return error.a;
+    }
+
+    fn a(x: X) void {
+        _ = x;
+    }
+};
+
+export fn entry() void {
+    const x = X.init();
+    x.a();
+}
+
+// error
+// backend=stage2
+// target=native
+//
+// :13:6: error: no field or member function named 'a' in '@typeInfo(@typeInfo(@TypeOf(tmp.X.init)).Fn.return_type.?).ErrorUnion.error_set!tmp.X'
+// :13:6: note: consider using 'try', 'catch', or 'if'