Rollup merge of #143245 - tgross35:metavariable-expr-organization, r=petrochenkov

mbe: Add tests and restructure metavariable expressions

Add tests that show better diagnostics, and factor `concat` handling to a separate function. Each commit message has further details.

This performs the nonfunctional perparation for further changes such as https://github.com/rust-lang/rust/pull/142950 and https://github.com/rust-lang/rust/pull/142975 .

1 files changed, 344 insertions, 0 deletions

diff --git a/tests/ui/macros/metavar-expressions/concat-usage-errors.stderr b/tests/ui/macros/metavar-expressions/concat-usage-errors.stderr
new file mode 100644
index 00000000000..8be3e792ec3
--- /dev/null
+++ b/tests/ui/macros/metavar-expressions/concat-usage-errors.stderr
@@ -0,0 +1,344 @@
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:7:10
+   |
+LL |         ${concat()}
+   |          ^^^^^^^^^^
+
+error: `concat` must have at least two elements
+  --> $DIR/concat-usage-errors.rs:10:11
+   |
+LL |         ${concat(aaaa)}
+   |           ^^^^^^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:13:10
+   |
+LL |         ${concat(aaaa,)}
+   |          ^^^^^^^^^^^^^^^
+
+error: expected comma
+  --> $DIR/concat-usage-errors.rs:18:10
+   |
+LL |         ${concat(aaaa aaaa)}
+   |          ^^^^^^^^^^^^^^^^^^^
+
+error: `concat` must have at least two elements
+  --> $DIR/concat-usage-errors.rs:21:11
+   |
+LL |         ${concat($ex)}
+   |           ^^^^^^
+
+error: expected comma
+  --> $DIR/concat-usage-errors.rs:27:10
+   |
+LL |         ${concat($ex, aaaa 123)}
+   |          ^^^^^^^^^^^^^^^^^^^^^^^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:30:10
+   |
+LL |         ${concat($ex, aaaa,)}
+   |          ^^^^^^^^^^^^^^^^^^^^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:90:26
+   |
+LL |         let ${concat(_a, 'b')}: () = ();
+   |                          ^^^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:93:26
+   |
+LL |         let ${concat(_a, 1)}: () = ();
+   |                          ^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:95:26
+   |
+LL |         let ${concat(_a, 1.5)}: () = ();
+   |                          ^^^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:97:26
+   |
+LL |         let ${concat(_a, c"hi")}: () = ();
+   |                          ^^^^^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:99:26
+   |
+LL |         let ${concat(_a, b"hi")}: () = ();
+   |                          ^^^^^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:101:26
+   |
+LL |         let ${concat(_a, b'b')}: () = ();
+   |                          ^^^^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:103:26
+   |
+LL |         let ${concat(_a, b'b')}: () = ();
+   |                          ^^^^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:106:30
+   |
+LL |         let ${concat($ident, 'b')}: () = ();
+   |                              ^^^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:108:30
+   |
+LL |         let ${concat($ident, 1)}: () = ();
+   |                              ^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:110:30
+   |
+LL |         let ${concat($ident, 1.5)}: () = ();
+   |                              ^^^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:112:30
+   |
+LL |         let ${concat($ident, c"hi")}: () = ();
+   |                              ^^^^^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:114:30
+   |
+LL |         let ${concat($ident, b"hi")}: () = ();
+   |                              ^^^^^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:116:30
+   |
+LL |         let ${concat($ident, b'b')}: () = ();
+   |                              ^^^^
+
+error: expected identifier or string literal
+  --> $DIR/concat-usage-errors.rs:118:30
+   |
+LL |         let ${concat($ident, b'b')}: () = ();
+   |                              ^^^^
+
+error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `tt`
+  --> $DIR/concat-usage-errors.rs:24:19
+   |
+LL |         ${concat($ex, aaaa)}
+   |                   ^^
+   |
+   = note: currently only string literals are supported
+
+error: variable `foo` is not recognized in meta-variable expression
+  --> $DIR/concat-usage-errors.rs:37:30
+   |
+LL |         const ${concat(FOO, $foo)}: i32 = 2;
+   |                              ^^^
+
+error: `${concat(..)}` is not generating a valid identifier
+  --> $DIR/concat-usage-errors.rs:44:14
+   |
+LL |         let ${concat("1", $ident)}: () = ();
+   |              ^^^^^^^^^^^^^^^^^^^^^
+...
+LL |     starting_number!(_abc);
+   |     ---------------------- in this macro invocation
+   |
+   = note: this error originates in the macro `starting_number` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: `${concat(..)}` is not generating a valid identifier
+  --> $DIR/concat-usage-errors.rs:57:14
+   |
+LL |         let ${concat("\u{00BD}", $ident)}: () = ();
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL |     starting_invalid_unicode!(_abc);
+   |     ------------------------------- in this macro invocation
+   |
+   = note: this error originates in the macro `starting_invalid_unicode` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: `${concat(..)}` is not generating a valid identifier
+  --> $DIR/concat-usage-errors.rs:76:14
+   |
+LL |         let ${concat($ident, "\u{00BD}")}: () = ();
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL |     ending_invalid_unicode!(_abc);
+   |     ----------------------------- in this macro invocation
+   |
+   = note: this error originates in the macro `ending_invalid_unicode` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: expected pattern, found `$`
+  --> $DIR/concat-usage-errors.rs:90:13
+   |
+LL |         let ${concat(_a, 'b')}: () = ();
+   |             ^ expected pattern
+...
+LL |     unsupported_literals!(_abc);
+   |     --------------------------- in this macro invocation
+   |
+   = note: this error originates in the macro `unsupported_literals` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: `${concat(..)}` is not generating a valid identifier
+  --> $DIR/concat-usage-errors.rs:83:14
+   |
+LL |         let ${concat("", "")}: () = ();
+   |              ^^^^^^^^^^^^^^^^
+...
+LL |     empty!();
+   |     -------- in this macro invocation
+   |
+   = note: this error originates in the macro `empty` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: `${concat(..)}` is not generating a valid identifier
+  --> $DIR/concat-usage-errors.rs:125:16
+   |
+LL |         const ${concat(_foo, $literal)}: () = ();
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL |     bad_literal_string!("\u{00BD}");
+   |     ------------------------------- in this macro invocation
+   |
+   = note: this error originates in the macro `bad_literal_string` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: `${concat(..)}` is not generating a valid identifier
+  --> $DIR/concat-usage-errors.rs:125:16
+   |
+LL |         const ${concat(_foo, $literal)}: () = ();
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL |     bad_literal_string!("\x41");
+   |     --------------------------- in this macro invocation
+   |
+   = note: this error originates in the macro `bad_literal_string` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: `${concat(..)}` is not generating a valid identifier
+  --> $DIR/concat-usage-errors.rs:125:16
+   |
+LL |         const ${concat(_foo, $literal)}: () = ();
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL |     bad_literal_string!("🤷");
+   |     ------------------------- in this macro invocation
+   |
+   = note: this error originates in the macro `bad_literal_string` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: `${concat(..)}` is not generating a valid identifier
+  --> $DIR/concat-usage-errors.rs:125:16
+   |
+LL |         const ${concat(_foo, $literal)}: () = ();
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL |     bad_literal_string!("d[-_-]b");
+   |     ------------------------------ in this macro invocation
+   |
+   = note: this error originates in the macro `bad_literal_string` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: `${concat(..)}` is not generating a valid identifier
+  --> $DIR/concat-usage-errors.rs:125:16
+   |
+LL |         const ${concat(_foo, $literal)}: () = ();
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL |     bad_literal_string!("-1");
+   |     ------------------------- in this macro invocation
+   |
+   = note: this error originates in the macro `bad_literal_string` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: `${concat(..)}` is not generating a valid identifier
+  --> $DIR/concat-usage-errors.rs:125:16
+   |
+LL |         const ${concat(_foo, $literal)}: () = ();
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL |     bad_literal_string!("1.0");
+   |     -------------------------- in this macro invocation
+   |
+   = note: this error originates in the macro `bad_literal_string` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: `${concat(..)}` is not generating a valid identifier
+  --> $DIR/concat-usage-errors.rs:125:16
+   |
+LL |         const ${concat(_foo, $literal)}: () = ();
+   |                ^^^^^^^^^^^^^^^^^^^^^^^^
+...
+LL |     bad_literal_string!("'1'");
+   |     -------------------------- in this macro invocation
+   |
+   = note: this error originates in the macro `bad_literal_string` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `tt`
+  --> $DIR/concat-usage-errors.rs:138:31
+   |
+LL |         const ${concat(_foo, $literal)}: () = ();
+   |                               ^^^^^^^
+   |
+   = note: currently only string literals are supported
+
+error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `tt`
+  --> $DIR/concat-usage-errors.rs:138:31
+   |
+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:138:31
+   |
+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:138:31
+   |
+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:138:31
+   |
+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
+   |
+LL |         const ${concat(_foo, $tt)}: () = ();
+   |                               ^^
+   |
+   = note: currently only string literals are supported
+
+error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `tt`
+  --> $DIR/concat-usage-errors.rs:149:31
+   |
+LL |         const ${concat(_foo, $tt)}: () = ();
+   |                               ^^
+   |
+   = note: currently only string literals are supported
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: metavariables of `${concat(..)}` must be of type `ident`, `literal` or `tt`
+  --> $DIR/concat-usage-errors.rs:149:31
+   |
+LL |         const ${concat(_foo, $tt)}: () = ();
+   |                               ^^
+   |
+   = note: currently only string literals are supported
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error: aborting due to 43 previous errors
+