diff --git a/src/Module.zig b/src/Module.zig
index e756cc3dfd..6056c385e3 100644
--- a/src/Module.zig
+++ b/src/Module.zig
@@ -4435,6 +4435,7 @@ pub fn semaFile(mod: *Module, file: *File) SemaError!void {
     new_decl.alive = true; // This Decl corresponds to a File and is therefore always alive.
     new_decl.analysis = .in_progress;
     new_decl.generation = mod.generation;
+    new_decl.name_fully_qualified = true;
 
     if (file.status == .success_zir) {
         assert(file.zir_loaded);
diff --git a/src/Sema.zig b/src/Sema.zig
index 7ad7491ea1..aed09d6201 100644
--- a/src/Sema.zig
+++ b/src/Sema.zig
@@ -4353,6 +4353,11 @@ fn failWithBadMemberAccess(
         .Enum => "enum",
         else => unreachable,
     };
+    if (sema.mod.declIsRoot(agg_ty.getOwnerDecl())) {
+        return sema.fail(block, field_src, "root struct of file '{}' has no member named '{s}'", .{
+            agg_ty.fmt(sema.mod), field_name,
+        });
+    }
     const msg = msg: {
         const msg = try sema.errMsg(block, field_src, "{s} '{}' has no member named '{s}'", .{
             kw_name, agg_ty.fmt(sema.mod), field_name,
diff --git a/test/cases/aarch64-macos/hello_world_with_updates.0.zig b/test/cases/aarch64-macos/hello_world_with_updates.0.zig
index 3c7a494180..9f516ff139 100644
--- a/test/cases/aarch64-macos/hello_world_with_updates.0.zig
+++ b/test/cases/aarch64-macos/hello_world_with_updates.0.zig
@@ -2,5 +2,4 @@
 // output_mode=Exe
 // target=aarch64-macos
 //
-// :109:9: error: struct 'tmp.tmp' has no member named 'main'
-// :7:1: note: struct declared here
+// :109:9: error: root struct of file 'tmp' has no member named 'main'
diff --git a/test/cases/compile_errors/bogus_compile_var.zig b/test/cases/compile_errors/bogus_compile_var.zig
index b675fd941c..be222e5393 100644
--- a/test/cases/compile_errors/bogus_compile_var.zig
+++ b/test/cases/compile_errors/bogus_compile_var.zig
@@ -5,5 +5,4 @@ export fn entry() usize { return @sizeOf(@TypeOf(x)); }
 // backend=stage2
 // target=native
 //
-// :1:29: error: struct 'builtin.builtin' has no member named 'bogus'
-// :1:1: note: struct declared here
+// :1:29: error: root struct of file 'builtin' has no member named 'bogus'
diff --git a/test/cases/compile_errors/issue_2032_compile_diagnostic_string_for_top_level_decl_type.zig b/test/cases/compile_errors/issue_2032_compile_diagnostic_string_for_top_level_decl_type.zig
index 9ae320650a..d78891bb2b 100644
--- a/test/cases/compile_errors/issue_2032_compile_diagnostic_string_for_top_level_decl_type.zig
+++ b/test/cases/compile_errors/issue_2032_compile_diagnostic_string_for_top_level_decl_type.zig
@@ -7,5 +7,5 @@ export fn entry() void {
 // backend=stage2
 // target=native
 //
-// :2:27: error: expected type 'u32', found 'tmp.tmp'
+// :2:27: error: expected type 'u32', found 'tmp'
 // :1:1: note: struct declared here
diff --git a/test/cases/x86_64-linux/hello_world_with_updates.0.zig b/test/cases/x86_64-linux/hello_world_with_updates.0.zig
index c9c94442d0..40abdd6c1f 100644
--- a/test/cases/x86_64-linux/hello_world_with_updates.0.zig
+++ b/test/cases/x86_64-linux/hello_world_with_updates.0.zig
@@ -2,5 +2,4 @@
 // output_mode=Exe
 // target=x86_64-linux
 //
-// :109:9: error: struct 'tmp.tmp' has no member named 'main'
-// :7:1: note: struct declared here
+// :109:9: error: root struct of file 'tmp' has no member named 'main'
diff --git a/test/cases/x86_64-macos/hello_world_with_updates.0.zig b/test/cases/x86_64-macos/hello_world_with_updates.0.zig
index 5860c9c0f6..e0680c81d7 100644
--- a/test/cases/x86_64-macos/hello_world_with_updates.0.zig
+++ b/test/cases/x86_64-macos/hello_world_with_updates.0.zig
@@ -2,5 +2,4 @@
 // output_mode=Exe
 // target=x86_64-macos
 //
-// :109:9: error: struct 'tmp.tmp' has no member named 'main'
-// :7:1: note: struct declared here
+// :109:9: error: root struct of file 'tmp' has no member named 'main'
diff --git a/test/cases/x86_64-windows/hello_world_with_updates.0.zig b/test/cases/x86_64-windows/hello_world_with_updates.0.zig
index 142699b9da..04e1d4cfad 100644
--- a/test/cases/x86_64-windows/hello_world_with_updates.0.zig
+++ b/test/cases/x86_64-windows/hello_world_with_updates.0.zig
@@ -2,5 +2,4 @@
 // output_mode=Exe
 // target=x86_64-windows
 //
-// :130:9: error: struct 'tmp.tmp' has no member named 'main'
-// :7:1: note: struct declared here
+// :130:9: error: root struct of file 'tmp' has no member named 'main'