Sema: improve bitcast to enum error

1 files changed, 16 insertions, 4 deletions

diff --git a/src/Sema.zig b/src/Sema.zig
index 862d5cbf48..08372bf7b3 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -7617,11 +7617,11 @@ fn zirBitcast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
     const extra = sema.code.extraData(Zir.Inst.Bin, inst_data.payload_index).data;
 
     const dest_ty = try sema.resolveType(block, dest_ty_src, extra.lhs);
+    const operand = try sema.resolveInst(extra.rhs);
     switch (dest_ty.zigTypeTag()) {
         .AnyFrame,
         .ComptimeFloat,
         .ComptimeInt,
-        .Enum,
         .EnumLiteral,
         .ErrorSet,
         .ErrorUnion,
@@ -7634,7 +7634,21 @@ fn zirBitcast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
         .Type,
         .Undefined,
         .Void,
-        => return sema.fail(block, dest_ty_src, "invalid type '{}' for @bitCast", .{dest_ty.fmt(sema.mod)}),
+        => return sema.fail(block, dest_ty_src, "cannot @bitCast to '{}'", .{dest_ty.fmt(sema.mod)}),
+
+        .Enum => {
+            const msg = msg: {
+                const msg = try sema.errMsg(block, dest_ty_src, "cannot @bitCast to '{}'", .{dest_ty.fmt(sema.mod)});
+                errdefer msg.destroy(sema.gpa);
+                switch (sema.typeOf(operand).zigTypeTag()) {
+                    .Int, .ComptimeInt => try sema.errNote(block, dest_ty_src, msg, "use @intToEnum for type coercion", .{}),
+                    else => {},
+                }
+
+                break :msg msg;
+            };
+            return sema.failWithOwnedErrorMsg(block, msg);
+        },
 
         .Pointer => return sema.fail(block, dest_ty_src, "cannot @bitCast to '{}', use @ptrCast to cast to a pointer", .{
             dest_ty.fmt(sema.mod),
@@ -7658,8 +7672,6 @@ fn zirBitcast(sema: *Sema, block: *Block, inst: Zir.Inst.Index) CompileError!Air
         .Vector,
         => {},
     }
-
-    const operand = try sema.resolveInst(extra.rhs);
     return sema.bitCast(block, dest_ty, operand, operand_src);
 }