diff --git a/src/Sema.zig b/src/Sema.zig
index ea6f4898c5..0d3f7eaf83 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -2566,8 +2566,19 @@ fn zirMergeErrorSets(sema: *Sema, block: *Scope.Block, inst: Zir.Inst.Index) Inn
     const src: LazySrcLoc = .{ .node_offset_bin_op = inst_data.src_node };
     const lhs_src: LazySrcLoc = .{ .node_offset_bin_lhs = inst_data.src_node };
     const rhs_src: LazySrcLoc = .{ .node_offset_bin_rhs = inst_data.src_node };
-    const lhs_ty = try sema.resolveType(block, lhs_src, extra.lhs);
-    const rhs_ty = try sema.resolveType(block, rhs_src, extra.rhs);
+    const lhs = try sema.resolveInst(extra.lhs);
+    const rhs = try sema.resolveInst(extra.rhs);
+    if (rhs.ty.zigTypeTag() == .Bool and lhs.ty.zigTypeTag() == .Bool) {
+        const msg = msg: {
+            const msg = try sema.mod.errMsg(&block.base, lhs_src, "expected error set type, found 'bool'", .{});
+            errdefer msg.destroy(sema.gpa);
+            try sema.mod.errNote(&block.base, src, msg, "'||' merges error sets; 'or' performs boolean OR", .{});
+            break :msg msg;
+        };
+        return sema.mod.failWithOwnedErrorMsg(&block.base, msg);
+    }
+    const rhs_ty = try sema.resolveAirAsType(block, rhs_src, rhs);
+    const lhs_ty = try sema.resolveAirAsType(block, lhs_src, lhs);
     if (rhs_ty.zigTypeTag() != .ErrorSet)
         return sema.mod.fail(&block.base, rhs_src, "expected error set type, found {}", .{rhs_ty});
     if (lhs_ty.zigTypeTag() != .ErrorSet)
diff --git a/test/cases.zig b/test/cases.zig
index fa66db8e34..cc0b924bb3 100644
--- a/test/cases.zig
+++ b/test/cases.zig
@@ -1481,6 +1481,15 @@ pub fn addCases(ctx: *TestContext) !void {
         ,
             "",
         );
+        case.addError(
+            \\pub fn main() void {
+            \\    const z = true || false;
+            \\    _ = z;
+            \\}
+        , &.{
+            ":2:15: error: expected error set type, found 'bool'",
+            ":2:20: note: '||' merges error sets; 'or' performs boolean OR",
+        });
     }
     {
         var case = ctx.exe("inline assembly", linux_x64);