diff --git a/src/Sema.zig b/src/Sema.zig
index d3ca6a8cc5..593b299833 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -6654,7 +6654,11 @@ fn zirFunc(
         src_locs = sema.code.extraData(Zir.Inst.Func.SrcLocs, extra_index).data;
     }
 
-    const cc: std.builtin.CallingConvention = if (sema.owner_decl.is_exported)
+    // If this instruction has a body it means it's the type of the `owner_decl`
+    // otherwise it's a function type without a `callconv` attribute and should
+    // never be `.C`.
+    // NOTE: revisit when doing #1717
+    const cc: std.builtin.CallingConvention = if (sema.owner_decl.is_exported and has_body)
         .C
     else
         .Unspecified;
diff --git a/test/cases/compile_errors/runtime_indexing_comptime_array.zig b/test/cases/compile_errors/runtime_indexing_comptime_array.zig
index da603d3630..3acd0feb61 100644
--- a/test/cases/compile_errors/runtime_indexing_comptime_array.zig
+++ b/test/cases/compile_errors/runtime_indexing_comptime_array.zig
@@ -23,9 +23,9 @@ pub export fn entry3() void {
 // error
 // backend=stage2,llvm
 //
-// :6:33: error: values of type '[2]fn() callconv(.C) void' must be comptime known, but index value is runtime known
-// :6:33: note: use '*const fn() callconv(.C) void' for a function pointer type
-// :13:33: error: values of type '[2]fn() callconv(.C) void' must be comptime known, but index value is runtime known
-// :13:33: note: use '*const fn() callconv(.C) void' for a function pointer type
-// :19:33: error: values of type '[2]fn() callconv(.C) void' must be comptime known, but index value is runtime known
-// :19:33: note: use '*const fn() callconv(.C) void' for a function pointer type
+// :6:5: error: values of type '[2]fn() void' must be comptime known, but index value is runtime known
+// :6:5: note: use '*const fn() void' for a function pointer type
+// :13:5: error: values of type '[2]fn() void' must be comptime known, but index value is runtime known
+// :13:5: note: use '*const fn() void' for a function pointer type
+// :19:5: error: values of type '[2]fn() void' must be comptime known, but index value is runtime known
+// :19:5: note: use '*const fn() void' for a function pointer type