errors: only eagerly translate subdiagnostics

Subdiagnostics don't need to be lazily translated, they can always be
eagerly translated. Eager translation is slightly more complex as we need
to have a `DiagCtxt` available to perform the translation, which involves
slightly more threading of that context.

This slight increase in complexity should enable later simplifications -
like passing `DiagCtxt` into `AddToDiagnostic` and moving Fluent messages
into the diagnostic structs rather than having them in separate files
(working on that was what led to this change).

Signed-off-by: David Wood <david@davidtw.co>

2 files changed, 33 insertions, 21 deletions

diff --git a/tests/ui-fulldeps/session-diagnostic/diagnostic-derive.rs b/tests/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
index d3cfd28082d..6cc6fdfc0eb 100644
--- a/tests/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
+++ b/tests/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
@@ -701,7 +701,7 @@ struct RawIdentDiagnosticArg {
 #[diag(no_crate_example)]
 struct SubdiagnosticBad {
     #[subdiagnostic(bad)]
-    //~^ ERROR `eager` is the only supported nested attribute for `subdiagnostic`
+    //~^ ERROR `#[subdiagnostic(...)]` is not a valid attribute
     note: Note,
 }
 
@@ -717,7 +717,7 @@ struct SubdiagnosticBadStr {
 #[diag(no_crate_example)]
 struct SubdiagnosticBadTwice {
     #[subdiagnostic(bad, bad)]
-    //~^ ERROR `eager` is the only supported nested attribute for `subdiagnostic`
+    //~^ ERROR `#[subdiagnostic(...)]` is not a valid attribute
     note: Note,
 }
 
@@ -725,7 +725,7 @@ struct SubdiagnosticBadTwice {
 #[diag(no_crate_example)]
 struct SubdiagnosticBadLitStr {
     #[subdiagnostic("bad")]
-    //~^ ERROR `eager` is the only supported nested attribute for `subdiagnostic`
+    //~^ ERROR `#[subdiagnostic(...)]` is not a valid attribute
     note: Note,
 }
 
@@ -739,8 +739,9 @@ struct SubdiagnosticEagerLint {
 
 #[derive(Diagnostic)]
 #[diag(no_crate_example)]
-struct SubdiagnosticEagerCorrect {
+struct SubdiagnosticEagerFormerlyCorrect {
     #[subdiagnostic(eager)]
+    //~^ ERROR `#[subdiagnostic(...)]` is not a valid attribute
     note: Note,
 }
 
@@ -761,6 +762,7 @@ pub(crate) struct SubdiagnosticWithSuggestion {
 #[diag(no_crate_example)]
 struct SubdiagnosticEagerSuggestion {
     #[subdiagnostic(eager)]
+    //~^ ERROR `#[subdiagnostic(...)]` is not a valid attribute
     sub: SubdiagnosticWithSuggestion,
 }
 
diff --git a/tests/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr b/tests/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
index 2032b8a972a..f2dbc718c76 100644
--- a/tests/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
+++ b/tests/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
@@ -468,11 +468,11 @@ LL | #[label]
    |
    = help: `#[label]` and `#[suggestion]` can only be applied to fields
 
-error: `eager` is the only supported nested attribute for `subdiagnostic`
-  --> $DIR/diagnostic-derive.rs:703:7
+error: `#[subdiagnostic(...)]` is not a valid attribute
+  --> $DIR/diagnostic-derive.rs:703:5
    |
 LL |     #[subdiagnostic(bad)]
-   |       ^^^^^^^^^^^^^
+   |     ^
 
 error: `#[subdiagnostic = ...]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:711:5
@@ -480,40 +480,50 @@ error: `#[subdiagnostic = ...]` is not a valid attribute
 LL |     #[subdiagnostic = "bad"]
    |     ^
 
-error: `eager` is the only supported nested attribute for `subdiagnostic`
-  --> $DIR/diagnostic-derive.rs:719:7
+error: `#[subdiagnostic(...)]` is not a valid attribute
+  --> $DIR/diagnostic-derive.rs:719:5
    |
 LL |     #[subdiagnostic(bad, bad)]
-   |       ^^^^^^^^^^^^^
+   |     ^
 
-error: `eager` is the only supported nested attribute for `subdiagnostic`
-  --> $DIR/diagnostic-derive.rs:727:7
+error: `#[subdiagnostic(...)]` is not a valid attribute
+  --> $DIR/diagnostic-derive.rs:727:5
    |
 LL |     #[subdiagnostic("bad")]
-   |       ^^^^^^^^^^^^^
+   |     ^
 
 error: `#[subdiagnostic(...)]` is not a valid attribute
   --> $DIR/diagnostic-derive.rs:735:5
    |
 LL |     #[subdiagnostic(eager)]
    |     ^
+
+error: `#[subdiagnostic(...)]` is not a valid attribute
+  --> $DIR/diagnostic-derive.rs:743:5
    |
-   = help: eager subdiagnostics are not supported on lints
+LL |     #[subdiagnostic(eager)]
+   |     ^
+
+error: `#[subdiagnostic(...)]` is not a valid attribute
+  --> $DIR/diagnostic-derive.rs:764:5
+   |
+LL |     #[subdiagnostic(eager)]
+   |     ^
 
 error: expected at least one string literal for `code(...)`
-  --> $DIR/diagnostic-derive.rs:793:23
+  --> $DIR/diagnostic-derive.rs:795:23
    |
 LL |     #[suggestion(code())]
    |                       ^
 
 error: `code(...)` must contain only string literals
-  --> $DIR/diagnostic-derive.rs:801:23
+  --> $DIR/diagnostic-derive.rs:803:23
    |
 LL |     #[suggestion(code(foo))]
    |                       ^^^
 
 error: `#[suggestion(...)]` is not a valid attribute
-  --> $DIR/diagnostic-derive.rs:825:5
+  --> $DIR/diagnostic-derive.rs:827:5
    |
 LL |     #[suggestion(no_crate_suggestion, code = "")]
    |     ^
@@ -529,13 +539,13 @@ LL | #[diag = "E0123"]
    |        ^ maybe a missing crate `core`?
 
 error[E0433]: failed to resolve: maybe a missing crate `core`?
-  --> $DIR/diagnostic-derive.rs:801:23
+  --> $DIR/diagnostic-derive.rs:803:23
    |
 LL |     #[suggestion(code(foo))]
    |                       ^^^ maybe a missing crate `core`?
 
 error[E0433]: failed to resolve: maybe a missing crate `core`?
-  --> $DIR/diagnostic-derive.rs:810:25
+  --> $DIR/diagnostic-derive.rs:812:25
    |
 LL |     #[suggestion(code = 3)]
    |                         ^ maybe a missing crate `core`?
@@ -601,7 +611,7 @@ LL | #[diag(nonsense, code = E0123)]
    |        ^^^^^^^^ not found in `crate::fluent_generated`
 
 error[E0425]: cannot find value `__code_34` in this scope
-  --> $DIR/diagnostic-derive.rs:807:10
+  --> $DIR/diagnostic-derive.rs:809:10
    |
 LL | #[derive(Diagnostic)]
    |          ^^^^^^^^^^ not found in this scope
@@ -622,7 +632,7 @@ note: required by a bound in `DiagnosticBuilder::<'a, G>::arg`
   --> $COMPILER_DIR/rustc_errors/src/diagnostic_builder.rs:LL:CC
    = note: this error originates in the macro `forward` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: aborting due to 84 previous errors
+error: aborting due to 86 previous errors
 
 Some errors have detailed explanations: E0277, E0425, E0433.
 For more information about an error, try `rustc --explain E0277`.