support integer literals in `${concat()}`

4 files changed, 62 insertions, 24 deletions

diff --git a/compiler/rustc_expand/src/mbe/transcribe.rs b/compiler/rustc_expand/src/mbe/transcribe.rs
index e4e4866b64c..ed8aa71d59d 100644
--- a/compiler/rustc_expand/src/mbe/transcribe.rs
+++ b/compiler/rustc_expand/src/mbe/transcribe.rs
@@ -940,11 +940,27 @@ fn extract_symbol_from_pnr<'a>(
         {
             Ok(*symbol)
         }
+        ParseNtResult::Literal(expr)
+            if let ExprKind::Lit(lit @ Lit { kind: LitKind::Integer, symbol, suffix }) =
+                &expr.kind =>
+        {
+            if lit.is_semantic_float() {
+                Err(dcx
+                    .struct_err("floats are not supported as metavariables of `${concat(..)}`")
+                    .with_span(span_err))
+            } else if suffix.is_none() {
+                Ok(*symbol)
+            } else {
+                Err(dcx
+                    .struct_err("integer metavariables of `${concat(..)}` must not be suffixed")
+                    .with_span(span_err))
+            }
+        }
         _ => Err(dcx
             .struct_err(
                 "metavariables of `${concat(..)}` must be of type `ident`, `literal` or `tt`",
             )
-            .with_note("currently only string literals are supported")
+            .with_note("currently only string and integer literals are supported")
             .with_span(span_err)),
     }
 }
diff --git a/tests/ui/macros/metavar-expressions/concat-allowed-operations.rs b/tests/ui/macros/metavar-expressions/concat-allowed-operations.rs
index 695a752fe17..5ac50c943d0 100644
--- a/tests/ui/macros/metavar-expressions/concat-allowed-operations.rs
+++ b/tests/ui/macros/metavar-expressions/concat-allowed-operations.rs
@@ -92,6 +92,12 @@ macro_rules! combinations {
     }};
 }
 
+macro_rules! int_struct {
+    ($n: literal) => {
+        struct ${concat(E, $n)};
+    }
+}
+
 fn main() {
     create_things!(behold);
     behold_separated_idents_in_a_fn();
@@ -112,4 +118,16 @@ fn main() {
     assert_eq!(VAR_123, 2);
 
     combinations!(_hello, "a", b, "b");
+
+    int_struct!(1_0);
+    int_struct!(2);
+    int_struct!(3___0);
+    int_struct!(7_);
+    int_struct!(08);
+
+    let _ = E1_0;
+    let _ = E2;
+    let _ = E3___0;
+    let _ = E7_;
+    let _ = E08;
 }
diff --git a/tests/ui/macros/metavar-expressions/concat-usage-errors.rs b/tests/ui/macros/metavar-expressions/concat-usage-errors.rs
index 7d8756de9e2..277ad240b1b 100644
--- a/tests/ui/macros/metavar-expressions/concat-usage-errors.rs
+++ b/tests/ui/macros/metavar-expressions/concat-usage-errors.rs
@@ -140,7 +140,9 @@ macro_rules! bad_literal_non_string {
         //~| ERROR metavariables of `${concat(..)}` must be of type
         //~| ERROR metavariables of `${concat(..)}` must be of type
         //~| ERROR metavariables of `${concat(..)}` must be of type
-        //~| ERROR metavariables of `${concat(..)}` must be of type
+        //~| ERROR floats are not supported as metavariables of `${concat(..)}`
+        //~| ERROR integer metavariables of `${concat(..)}` must not be suffixed
+        //~| ERROR integer metavariables of `${concat(..)}` must not be suffixed
     }
 }
 
@@ -149,7 +151,6 @@ macro_rules! bad_tt_literal {
         const ${concat(_foo, $tt)}: () = ();
         //~^ ERROR metavariables of `${concat(..)}` must be of type
         //~| ERROR metavariables of `${concat(..)}` must be of type
-        //~| ERROR metavariables of `${concat(..)}` must be of type
     }
 }
 
@@ -178,13 +179,14 @@ fn main() {
     bad_literal_string!("1.0");
     bad_literal_string!("'1'");
 
-    bad_literal_non_string!(1);
     bad_literal_non_string!(-1);
     bad_literal_non_string!(1.0);
     bad_literal_non_string!('1');
     bad_literal_non_string!(false);
+    bad_literal_non_string!(4f64);
+    bad_literal_non_string!(5u8);
+    bad_literal_non_string!(6_u8);
 
-    bad_tt_literal!(1);
     bad_tt_literal!(1.0);
     bad_tt_literal!('1');
 }
diff --git a/tests/ui/macros/metavar-expressions/concat-usage-errors.stderr b/tests/ui/macros/metavar-expressions/concat-usage-errors.stderr
index 8be3e792ec3..c124b76cb78 100644
--- a/tests/ui/macros/metavar-expressions/concat-usage-errors.stderr
+++ b/tests/ui/macros/metavar-expressions/concat-usage-errors.stderr
@@ -130,7 +130,7 @@ error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `t
 LL |         ${concat($ex, aaaa)}
    |                   ^^
    |
-   = note: currently only string literals are supported
+   = note: currently only string and integer literals are supported
 
 error: variable `foo` is not recognized in meta-variable expression
   --> $DIR/concat-usage-errors.rs:37:30
@@ -276,7 +276,7 @@ error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `t
 LL |         const ${concat(_foo, $literal)}: () = ();
    |                               ^^^^^^^
    |
-   = note: currently only string literals are supported
+   = note: currently only string and integer literals are supported
 
 error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `tt`
   --> $DIR/concat-usage-errors.rs:138:31
@@ -284,7 +284,7 @@ error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `t
 LL |         const ${concat(_foo, $literal)}: () = ();
    |                               ^^^^^^^
    |
-   = note: currently only string literals are supported
+   = note: currently only string and integer literals are supported
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `tt`
@@ -293,7 +293,7 @@ error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `t
 LL |         const ${concat(_foo, $literal)}: () = ();
    |                               ^^^^^^^
    |
-   = note: currently only string literals are supported
+   = note: currently only string and integer literals are supported
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `tt`
@@ -302,43 +302,45 @@ error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `t
 LL |         const ${concat(_foo, $literal)}: () = ();
    |                               ^^^^^^^
    |
-   = note: currently only string literals are supported
+   = note: currently only string and integer literals are supported
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
-error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `tt`
+error: floats are not supported as metavariables of `${concat(..)}`
   --> $DIR/concat-usage-errors.rs:138:31
    |
 LL |         const ${concat(_foo, $literal)}: () = ();
    |                               ^^^^^^^
+
+error: integer metavariables of `${concat(..)}` must not be suffixed
+  --> $DIR/concat-usage-errors.rs:138:31
    |
-   = note: currently only string literals are supported
-   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+LL |         const ${concat(_foo, $literal)}: () = ();
+   |                               ^^^^^^^
 
-error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `tt`
-  --> $DIR/concat-usage-errors.rs:149:31
+error: integer metavariables of `${concat(..)}` must not be suffixed
+  --> $DIR/concat-usage-errors.rs:138:31
    |
-LL |         const ${concat(_foo, $tt)}: () = ();
-   |                               ^^
+LL |         const ${concat(_foo, $literal)}: () = ();
+   |                               ^^^^^^^
    |
-   = note: currently only string literals are supported
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
 error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `tt`
-  --> $DIR/concat-usage-errors.rs:149:31
+  --> $DIR/concat-usage-errors.rs:151:31
    |
 LL |         const ${concat(_foo, $tt)}: () = ();
    |                               ^^
    |
-   = note: currently only string literals are supported
-   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+   = note: currently only string and integer literals are supported
 
 error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `tt`
-  --> $DIR/concat-usage-errors.rs:149:31
+  --> $DIR/concat-usage-errors.rs:151:31
    |
 LL |         const ${concat(_foo, $tt)}: () = ();
    |                               ^^
    |
-   = note: currently only string literals are supported
+   = note: currently only string and integer literals are supported
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
-error: aborting due to 43 previous errors
+error: aborting due to 44 previous errors