Rollup merge of #144409 - GuillaumeGomez:macro-expansion-early-abort, r=oli-obk

Stop compilation early if macro expansion failed

Fixes rust-lang/rust#116180.

So there isn't really a type that is central for macro expansion and some errors are actually emitted (because the resolution happens after the expansion I suppose) after the expansion pass (like "not found macro"). Sometimes, errors are only emitted on the second "try" (to improve error output). So I couldn't reach a similar solution than what was done in https://github.com/rust-lang/rust/pull/133937 and suggested by ````@estebank```` in https://github.com/rust-lang/rust/issues/116180#issuecomment-3109468922. But maybe I missed something?

So in the end, I realized that there is method called every time (except one, described below) a macro error is actually emitted: `ExtCtxt::trace_macros_diag`. Considering I updated what it did, I renamed it into `macro_error_and_trace_macros_diag` to better reflect it.

There is only one call of `trace_macros_diag` which isn't reporting an error but just used for `macro_trace` feature, so I kept it as is.

r? ````@oli-obk````

4 files changed, 32 insertions, 18 deletions

diff --git a/tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate-macro.rs b/tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate-macro.rs
new file mode 100644
index 00000000000..9d86ebc5331
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate-macro.rs
@@ -0,0 +1,14 @@
+// gate-test-if_let_guard
+
+fn main() {
+    macro_rules! use_expr {
+        ($e:expr) => {
+            match () {
+                () if $e => {}
+                _ => {}
+            }
+        }
+    }
+    use_expr!(let 0 = 1);
+    //~^ ERROR no rules expected keyword `let`
+}
diff --git a/tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate-macro.stderr b/tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate-macro.stderr
new file mode 100644
index 00000000000..411fde890a1
--- /dev/null
+++ b/tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate-macro.stderr
@@ -0,0 +1,17 @@
+error: no rules expected keyword `let`
+  --> $DIR/feature-gate-macro.rs:12:15
+   |
+LL |     macro_rules! use_expr {
+   |     --------------------- when calling this macro
+...
+LL |     use_expr!(let 0 = 1);
+   |               ^^^ no rules expected this token in macro call
+   |
+note: while trying to match meta-variable `$e:expr`
+  --> $DIR/feature-gate-macro.rs:5:10
+   |
+LL |         ($e:expr) => {
+   |          ^^^^^^^
+
+error: aborting due to 1 previous error
+
diff --git a/tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate.rs b/tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate.rs
index b1e305834cb..eb9e5dff37e 100644
--- a/tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate.rs
+++ b/tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate.rs
@@ -64,8 +64,6 @@ fn _macros() {
         //~^ ERROR `if let` guards are experimental
         _ => {}
     }
-    use_expr!(let 0 = 1);
-    //~^ ERROR no rules expected keyword `let`
 }
 
 fn main() {}
diff --git a/tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate.stderr b/tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate.stderr
index 19d1f4b0a57..759f1478350 100644
--- a/tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate.stderr
+++ b/tests/ui/rfcs/rfc-2294-if-let-guard/feature-gate.stderr
@@ -149,21 +149,6 @@ LL |     use_expr!((let 0 = 1));
    = note: only supported directly in conditions of `if` and `while` expressions
    = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
 
-error: no rules expected keyword `let`
-  --> $DIR/feature-gate.rs:67:15
-   |
-LL |     macro_rules! use_expr {
-   |     --------------------- when calling this macro
-...
-LL |     use_expr!(let 0 = 1);
-   |               ^^^ no rules expected this token in macro call
-   |
-note: while trying to match meta-variable `$e:expr`
-  --> $DIR/feature-gate.rs:48:10
-   |
-LL |         ($e:expr) => {
-   |          ^^^^^^^
-
 error[E0658]: `if let` guards are experimental
   --> $DIR/feature-gate.rs:7:12
    |
@@ -230,6 +215,6 @@ LL |         () if let 0 = 1 => {}
    = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
    = help: you can write `if matches!(<expr>, <pattern>)` instead of `if let <pattern> = <expr>`
 
-error: aborting due to 20 previous errors
+error: aborting due to 19 previous errors
 
 For more information about this error, try `rustc --explain E0658`.