Rollup merge of #103209 - Xiretza:multiple-suggestions, r=davidtwco

Diagnostic derives: allow specifying multiple alternative suggestions

This allows porting `span_suggestions()` to diagnostic structs.

Doesn't work for `multipart_suggestions()` because the rank would be reversed - the struct would specify multiple spans, each of which has multiple possible replacements, while `multipart_suggestions()` creates multiple possible replacements, each with multiple spans.

4 files changed, 133 insertions, 2 deletions

diff --git a/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs b/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
index 46164d573b0..ca77e483d6f 100644
--- a/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
+++ b/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.rs
@@ -758,3 +758,41 @@ struct WithDocComment {
     #[primary_span]
     span: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag(compiletest_example)]
+struct SuggestionsGood {
+    #[suggestion(code("foo", "bar"))]
+    sub: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(compiletest_example)]
+struct SuggestionsSingleItem {
+    #[suggestion(code("foo"))]
+    sub: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(compiletest_example)]
+struct SuggestionsNoItem {
+    #[suggestion(code())]
+    //~^ ERROR expected at least one string literal for `code(...)`
+    sub: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(compiletest_example)]
+struct SuggestionsInvalidItem {
+    #[suggestion(code(foo))]
+    //~^ ERROR `code(...)` must contain only string literals
+    sub: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(compiletest_example)]
+struct SuggestionsInvalidLiteral {
+    #[suggestion(code = 3)]
+    //~^ ERROR `code = "..."`/`code(...)` must contain only string literals
+    sub: Span,
+}
diff --git a/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr b/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
index 0a1c4bddb06..859c272b6ba 100644
--- a/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
+++ b/src/test/ui-fulldeps/session-diagnostic/diagnostic-derive.stderr
@@ -573,6 +573,24 @@ LL |     #[subdiagnostic(eager)]
    |
    = help: eager subdiagnostics are not supported on lints
 
+error: expected at least one string literal for `code(...)`
+  --> $DIR/diagnostic-derive.rs:779:18
+   |
+LL |     #[suggestion(code())]
+   |                  ^^^^^^
+
+error: `code(...)` must contain only string literals
+  --> $DIR/diagnostic-derive.rs:787:23
+   |
+LL |     #[suggestion(code(foo))]
+   |                       ^^^
+
+error: `code = "..."`/`code(...)` must contain only string literals
+  --> $DIR/diagnostic-derive.rs:795:18
+   |
+LL |     #[suggestion(code = 3)]
+   |                  ^^^^^^^^
+
 error: cannot find attribute `nonsense` in this scope
   --> $DIR/diagnostic-derive.rs:55:3
    |
@@ -647,7 +665,7 @@ LL |         arg: impl IntoDiagnosticArg,
    |                   ^^^^^^^^^^^^^^^^^ required by this bound in `DiagnosticBuilder::<'a, G>::set_arg`
    = note: this error originates in the derive macro `Diagnostic` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: aborting due to 80 previous errors
+error: aborting due to 83 previous errors
 
 Some errors have detailed explanations: E0277, E0425.
 For more information about an error, try `rustc --explain E0277`.
diff --git a/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.rs b/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.rs
index 9088ca6ce46..efec85eb52c 100644
--- a/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.rs
+++ b/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.rs
@@ -661,3 +661,48 @@ enum BL {
         span: Span,
     }
 }
+
+#[derive(Subdiagnostic)]
+#[multipart_suggestion(parser_add_paren)]
+struct BM {
+    #[suggestion_part(code("foo"))]
+    //~^ ERROR expected exactly one string literal for `code = ...`
+    span: Span,
+    r#type: String,
+}
+
+#[derive(Subdiagnostic)]
+#[multipart_suggestion(parser_add_paren)]
+struct BN {
+    #[suggestion_part(code("foo", "bar"))]
+    //~^ ERROR expected exactly one string literal for `code = ...`
+    span: Span,
+    r#type: String,
+}
+
+#[derive(Subdiagnostic)]
+#[multipart_suggestion(parser_add_paren)]
+struct BO {
+    #[suggestion_part(code(3))]
+    //~^ ERROR expected exactly one string literal for `code = ...`
+    span: Span,
+    r#type: String,
+}
+
+#[derive(Subdiagnostic)]
+#[multipart_suggestion(parser_add_paren)]
+struct BP {
+    #[suggestion_part(code())]
+    //~^ ERROR expected exactly one string literal for `code = ...`
+    span: Span,
+    r#type: String,
+}
+
+#[derive(Subdiagnostic)]
+#[multipart_suggestion(parser_add_paren)]
+struct BQ {
+    #[suggestion_part(code = 3)]
+    //~^ ERROR `code = "..."`/`code(...)` must contain only string literals
+    span: Span,
+    r#type: String,
+}
diff --git a/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr b/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr
index b21f9cc94a9..a85a8711eac 100644
--- a/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr
+++ b/src/test/ui-fulldeps/session-diagnostic/subdiagnostic-derive.stderr
@@ -415,6 +415,36 @@ error: `#[applicability]` has no effect if all `#[suggestion]`/`#[multipart_sugg
 LL |     #[applicability]
    |     ^^^^^^^^^^^^^^^^
 
+error: expected exactly one string literal for `code = ...`
+  --> $DIR/subdiagnostic-derive.rs:668:23
+   |
+LL |     #[suggestion_part(code("foo"))]
+   |                       ^^^^^^^^^^^
+
+error: expected exactly one string literal for `code = ...`
+  --> $DIR/subdiagnostic-derive.rs:677:23
+   |
+LL |     #[suggestion_part(code("foo", "bar"))]
+   |                       ^^^^^^^^^^^^^^^^^^
+
+error: expected exactly one string literal for `code = ...`
+  --> $DIR/subdiagnostic-derive.rs:686:23
+   |
+LL |     #[suggestion_part(code(3))]
+   |                       ^^^^^^^
+
+error: expected exactly one string literal for `code = ...`
+  --> $DIR/subdiagnostic-derive.rs:695:23
+   |
+LL |     #[suggestion_part(code())]
+   |                       ^^^^^^
+
+error: `code = "..."`/`code(...)` must contain only string literals
+  --> $DIR/subdiagnostic-derive.rs:704:23
+   |
+LL |     #[suggestion_part(code = 3)]
+   |                       ^^^^^^^^
+
 error: cannot find attribute `foo` in this scope
   --> $DIR/subdiagnostic-derive.rs:63:3
    |
@@ -475,6 +505,6 @@ error[E0425]: cannot find value `slug` in module `rustc_errors::fluent`
 LL | #[label(slug)]
    |         ^^^^ not found in `rustc_errors::fluent`
 
-error: aborting due to 67 previous errors
+error: aborting due to 72 previous errors
 
 For more information about this error, try `rustc --explain E0425`.