From 4c750016eb9b1c0831cbb0398a4d6ee9dbdc932e Mon Sep 17 00:00:00 2001
From: Loris Cro <kappaloris@gmail.com>
Date: Wed, 3 Aug 2022 17:21:56 +0200
Subject: [PATCH] autodoc: inferred error unions in function return values

---
 lib/docs/main.js | 14 +++++++++++++-
 src/Autodoc.zig  | 20 ++++++++++++++++----
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/lib/docs/main.js b/lib/docs/main.js
index 5435efd647..5ee39ec893 100644
--- a/lib/docs/main.js
+++ b/lib/docs/main.js
@@ -826,7 +826,13 @@ var zigAnalysis;
      
     function exprName(expr, opts) {
         switch (Object.keys(expr)[0]) {
-          default: throw "oh no";
+          default: throw "this expression is not implemented yet";
+          case "bool": {
+            if (expr.bool) {
+                return "true";
+            }
+            return "false";
+          }
           case "&": {
             return "&" + exprName(zigAnalysis.exprs[expr["&"]]);
           }
@@ -1699,6 +1705,12 @@ var zigAnalysis;
                     let rhs = exprName(errUnionObj.rhs, opts);
                     return lhs + "!" + rhs;
                   }
+                  case typeKinds.InferredErrorUnion:
+                  {
+                    let errUnionObj = (typeObj);
+                    let payload = exprName(errUnionObj.payload, opts);
+                    return "!" + payload;
+                  }
                   case typeKinds.Fn:
                   {
                       let fnObj = (typeObj);
diff --git a/src/Autodoc.zig b/src/Autodoc.zig
index 35f9dc7dea..a98ad7aee0 100644
--- a/src/Autodoc.zig
+++ b/src/Autodoc.zig
@@ -468,7 +468,7 @@ const DocData = struct {
             child: Expr,
         },
         ErrorUnion: struct { lhs: Expr, rhs: Expr },
-        // ErrorUnion: struct { name: []const u8 },
+        InferredErrorUnion: struct { payload: Expr },
         ErrorSet: struct {
             name: []const u8,
             fields: ?[]const Field = null,
@@ -582,7 +582,7 @@ const DocData = struct {
         typeOf: usize, // index in `exprs`
         typeInfo: usize, // index in `exprs`
         typeOf_peer: []usize,
-        errorUnion: usize, // index in `exprs`
+        errorUnion: usize, // index in `types`
         as: As,
         sizeOf: usize, // index in `exprs`
         bitSizeOf: usize, // index in `exprs`
@@ -1929,7 +1929,7 @@ fn walkInstruction(
                 .comptimeExpr = self.comptime_exprs.items.len,
             } };
             try self.comptime_exprs.append(self.arena, .{
-                .code = "if(banana) 1 else 0",
+                .code = "if (...) { ... }",
             });
             return res;
         },
@@ -2119,6 +2119,7 @@ fn walkInstruction(
                 inst_index,
                 self_ast_node_index,
                 type_slot_index,
+                tags[inst_index] == .func_inferred,
             );
 
             return result;
@@ -3416,6 +3417,7 @@ fn analyzeFunction(
     inst_index: usize,
     self_ast_node_index: usize,
     type_slot_index: usize,
+    ret_is_inferred_error_set: bool,
 ) AutodocErrors!DocData.WalkResult {
     const tags = file.zir.instructions.items(.tag);
     const data = file.zir.instructions.items(.data);
@@ -3522,13 +3524,23 @@ fn analyzeFunction(
         else => null,
     };
 
+    const ret_type: DocData.Expr = blk: {
+        if (ret_is_inferred_error_set) {
+            const ret_type_slot_index = self.types.items.len;
+            try self.types.append(self.arena, .{
+                .InferredErrorUnion = .{ .payload = ret_type_ref },
+            });
+            break :blk .{ .type = ret_type_slot_index };
+        } else break :blk ret_type_ref;
+    };
+
     self.ast_nodes.items[self_ast_node_index].fields = param_ast_indexes.items;
     self.types.items[type_slot_index] = .{
         .Fn = .{
             .name = "todo_name func",
             .src = self_ast_node_index,
             .params = param_type_refs.items,
-            .ret = ret_type_ref,
+            .ret = ret_type,
             .generic_ret = generic_ret,
         },
     };