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, 80 insertions, 44 deletions

diff --git a/tests/ui/const-generics/min_const_generics/macro-fail-const.rs b/tests/ui/const-generics/min_const_generics/macro-fail-const.rs
new file mode 100644
index 00000000000..619d6de7ad2
--- /dev/null
+++ b/tests/ui/const-generics/min_const_generics/macro-fail-const.rs
@@ -0,0 +1,23 @@
+trait Marker<const N: usize> {}
+struct Example<const N: usize>;
+impl<const N: usize> Marker<N> for Example<N> {}
+
+fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
+  //~^ ERROR: type provided when a constant was expected
+  //~| ERROR: type provided when a constant was expected
+  Example::<gimme_a_const!(marker)>
+  //~^ ERROR: type provided when a constant was expected
+}
+
+fn main() {
+  let _ok = Example::<{
+    #[macro_export]
+    macro_rules! gimme_a_const {
+      ($rusty: ident) => {{ let $rusty = 3; *&$rusty }}
+      //~^ ERROR expected type
+      //~| ERROR expected type
+    }
+    gimme_a_const!(run)
+  }>;
+  let _ok = Example::<{gimme_a_const!(marker)}>;
+}
diff --git a/tests/ui/const-generics/min_const_generics/macro-fail-const.stderr b/tests/ui/const-generics/min_const_generics/macro-fail-const.stderr
new file mode 100644
index 00000000000..2d8cb50834b
--- /dev/null
+++ b/tests/ui/const-generics/min_const_generics/macro-fail-const.stderr
@@ -0,0 +1,51 @@
+error: expected type, found `{`
+  --> $DIR/macro-fail-const.rs:16:27
+   |
+LL | fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
+   |                                 ----------------------
+   |                                 |
+   |                                 this macro call doesn't expand to a type
+   |                                 in this macro invocation
+...
+LL |       ($rusty: ident) => {{ let $rusty = 3; *&$rusty }}
+   |                           ^ expected type
+   |
+   = note: this error originates in the macro `gimme_a_const` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: expected type, found `{`
+  --> $DIR/macro-fail-const.rs:16:27
+   |
+LL |   Example::<gimme_a_const!(marker)>
+   |             ----------------------
+   |             |
+   |             this macro call doesn't expand to a type
+   |             in this macro invocation
+...
+LL |       ($rusty: ident) => {{ let $rusty = 3; *&$rusty }}
+   |                           ^ expected type
+   |
+   = note: this error originates in the macro `gimme_a_const` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error[E0747]: type provided when a constant was expected
+  --> $DIR/macro-fail-const.rs:5:33
+   |
+LL | fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
+   |                                 ^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0747]: type provided when a constant was expected
+  --> $DIR/macro-fail-const.rs:5:33
+   |
+LL | fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
+   |                                 ^^^^^^^^^^^^^^^^^^^^^^
+   |
+   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
+
+error[E0747]: type provided when a constant was expected
+  --> $DIR/macro-fail-const.rs:8:13
+   |
+LL |   Example::<gimme_a_const!(marker)>
+   |             ^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 5 previous errors
+
+For more information about this error, try `rustc --explain E0747`.
diff --git a/tests/ui/const-generics/min_const_generics/macro-fail.rs b/tests/ui/const-generics/min_const_generics/macro-fail.rs
index 8cfa5293cc2..ada9400b2a3 100644
--- a/tests/ui/const-generics/min_const_generics/macro-fail.rs
+++ b/tests/ui/const-generics/min_const_generics/macro-fail.rs
@@ -12,10 +12,7 @@ trait Marker<const N: usize> {}
 impl<const N: usize> Marker<N> for Example<N> {}
 
 fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
-  //~^ ERROR: type provided when a constant was expected
-  //~| ERROR: type provided when a constant was expected
   Example::<gimme_a_const!(marker)>
-  //~^ ERROR: type provided when a constant was expected
 }
 
 fn from_marker(_: impl Marker<{
@@ -35,9 +32,7 @@ fn main() {
   }>;
 
   let _fail = Example::<external_macro!()>;
-  //~^ ERROR: type provided when a constant
 
   let _fail = Example::<gimme_a_const!()>;
-  //~^ ERROR unexpected end of macro invocation
-  //~| ERROR: type provided when a constant was expected
+  //~^ ERROR: unexpected end of macro invocation
 }
diff --git a/tests/ui/const-generics/min_const_generics/macro-fail.stderr b/tests/ui/const-generics/min_const_generics/macro-fail.stderr
index 34764982bb0..b1d766cbfb6 100644
--- a/tests/ui/const-generics/min_const_generics/macro-fail.stderr
+++ b/tests/ui/const-generics/min_const_generics/macro-fail.stderr
@@ -1,5 +1,5 @@
 error: expected type, found `{`
-  --> $DIR/macro-fail.rs:30:27
+  --> $DIR/macro-fail.rs:27:27
    |
 LL | fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
    |                                 ----------------------
@@ -13,7 +13,7 @@ LL |       ($rusty: ident) => {{ let $rusty = 3; *&$rusty }}
    = note: this error originates in the macro `gimme_a_const` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: expected type, found `{`
-  --> $DIR/macro-fail.rs:30:27
+  --> $DIR/macro-fail.rs:27:27
    |
 LL |   Example::<gimme_a_const!(marker)>
    |             ----------------------
@@ -41,7 +41,7 @@ LL |   let _fail = Example::<external_macro!()>;
    = note: this error originates in the macro `external_macro` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: unexpected end of macro invocation
-  --> $DIR/macro-fail.rs:40:25
+  --> $DIR/macro-fail.rs:36:25
    |
 LL |     macro_rules! gimme_a_const {
    |     -------------------------- when calling this macro
@@ -50,43 +50,10 @@ LL |   let _fail = Example::<gimme_a_const!()>;
    |                         ^^^^^^^^^^^^^^^^ missing tokens in macro arguments
    |
 note: while trying to match meta-variable `$rusty:ident`
-  --> $DIR/macro-fail.rs:30:8
+  --> $DIR/macro-fail.rs:27:8
    |
 LL |       ($rusty: ident) => {{ let $rusty = 3; *&$rusty }}
    |        ^^^^^^^^^^^^^
 
-error[E0747]: type provided when a constant was expected
-  --> $DIR/macro-fail.rs:14:33
-   |
-LL | fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
-   |                                 ^^^^^^^^^^^^^^^^^^^^^^
-
-error[E0747]: type provided when a constant was expected
-  --> $DIR/macro-fail.rs:14:33
-   |
-LL | fn make_marker() -> impl Marker<gimme_a_const!(marker)> {
-   |                                 ^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
-
-error[E0747]: type provided when a constant was expected
-  --> $DIR/macro-fail.rs:17:13
-   |
-LL |   Example::<gimme_a_const!(marker)>
-   |             ^^^^^^^^^^^^^^^^^^^^^^
-
-error[E0747]: type provided when a constant was expected
-  --> $DIR/macro-fail.rs:37:25
-   |
-LL |   let _fail = Example::<external_macro!()>;
-   |                         ^^^^^^^^^^^^^^^^^
-
-error[E0747]: type provided when a constant was expected
-  --> $DIR/macro-fail.rs:40:25
-   |
-LL |   let _fail = Example::<gimme_a_const!()>;
-   |                         ^^^^^^^^^^^^^^^^
-
-error: aborting due to 9 previous errors
+error: aborting due to 4 previous errors
 
-For more information about this error, try `rustc --explain E0747`.