Add more test cases for untranslatable_diagnostic lint

Author: GrigorenkoPV

tests/ui-fulldeps/internal-lints/diagnostics.rs

@@ -117,4 +117,11 @@ pub fn skipped_because_of_annotation<'a>(dcx: DiagCtxtHandle<'a>) {
 fn f(_x: impl Into<DiagMessage>, _y: impl Into<SubdiagMessage>) {}
 fn g() {
     f(crate::fluent_generated::no_crate_example, crate::fluent_generated::no_crate_example);
+    f("untranslatable diagnostic", crate::fluent_generated::no_crate_example);
+    //~^ ERROR diagnostics should be created using translatable messages
+    f(crate::fluent_generated::no_crate_example, "untranslatable diagnostic");
+    //~^ ERROR diagnostics should be created using translatable messages
+    f("untranslatable diagnostic", "untranslatable diagnostic");
+    //~^ ERROR diagnostics should be created using translatable messages
+    //~^^ ERROR diagnostics should be created using translatable messages
 }

tests/ui-fulldeps/internal-lints/diagnostics.stderr

@@ -46,5 +46,31 @@ error: diagnostics should be created using translatable messages
 LL |     let _diag = dcx.struct_err("untranslatable diagnostic");
    |                     ^^^^^^^^^^
 
-error: aborting due to 6 previous errors
+error: diagnostics should be created using translatable messages
+  --> $DIR/diagnostics.rs:120:5
+   |
+LL |     f("untranslatable diagnostic", crate::fluent_generated::no_crate_example);
+   |     ^
+
+error: diagnostics should be created using translatable messages
+  --> $DIR/diagnostics.rs:122:5
+   |
+LL |     f(crate::fluent_generated::no_crate_example, "untranslatable diagnostic");
+   |     ^
+
+error: diagnostics should be created using translatable messages
+  --> $DIR/diagnostics.rs:124:5
+   |
+LL |     f("untranslatable diagnostic", "untranslatable diagnostic");
+   |     ^
+
+error: diagnostics should be created using translatable messages
+  --> $DIR/diagnostics.rs:124:5
+   |
+LL |     f("untranslatable diagnostic", "untranslatable diagnostic");
+   |     ^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 10 previous errors