ignore generics args in attribute paths

compiler/rustc_parse/src/parser/path.rs

@@ -178,12 +178,20 @@ impl<'a> Parser<'a> {
                     .map(|arg| arg.span())
                     .collect::<Vec<_>>();
                 parser.dcx().emit_err(errors::GenericsInPath { span });
+                // Ignore these arguments to prevent unexpected behaviors.
+                let segments = path
+                    .segments
+                    .iter()
+                    .map(|segment| PathSegment { ident: segment.ident, id: segment.id, args: None })
+                    .collect();
+                Some(Path { span: path.span, segments, tokens: path.tokens.clone() })
+            } else {
+                None
             }
         };
 
         maybe_whole!(self, NtPath, |path| {
-            reject_generics_if_mod_style(self, &path);
-            path.into_inner()
+            reject_generics_if_mod_style(self, &path).unwrap_or_else(|| path.into_inner())
         });
 
         if let token::Interpolated(nt) = &self.token.kind {

tests/crashes/97006.rs → tests/ui/macros/genercs-in-path-with-prettry-hir.rs

@@ -1,7 +1,6 @@
-//@ known-bug: #97006
 //@ compile-flags: -Zunpretty=hir
 
-#![allow(unused)]
+// issue#97006
 
 macro_rules! m {
     ($attr_path: path) => {

tests/ui/macros/genercs-in-path-with-prettry-hir.stderr

@@ -0,0 +1,8 @@
+error: unexpected generic arguments in path
+  --> $DIR/genercs-in-path-with-prettry-hir.rs:12:10
+   |
+LL | m!(inline<u8>);
+   |          ^^^^
+
+error: aborting due to 1 previous error
+

tests/ui/macros/genercs-in-path-with-prettry-hir.stdout

@@ -0,0 +1,15 @@
+#[prelude_import]
+use ::std::prelude::rust_2015::*;
+#[macro_use]
+extern crate std;
+//@ compile-flags: -Zunpretty=hir
+
+// issue#97006
+
+macro_rules! m { ($attr_path: path) => { #[$attr_path] fn f() {} } }
+#[
+
+inline]
+fn f() { }
+
+fn main() { }

tests/ui/macros/macro-expand-within-generics-in-path.rs

@@ -0,0 +1,19 @@
+// issue#123911
+// issue#123912
+
+macro_rules! m {
+    ($p: path) => {
+        #[$p]
+        struct S;
+    };
+}
+
+macro_rules! p {
+    () => {};
+}
+
+m!(generic<p!()>);
+//~^ ERROR: unexpected generic arguments in path
+//~| ERROR: cannot find attribute `generic` in this scope
+
+fn main() {}

tests/ui/macros/macro-expand-within-generics-in-path.stderr

@@ -0,0 +1,14 @@
+error: unexpected generic arguments in path
+  --> $DIR/macro-expand-within-generics-in-path.rs:15:11
+   |
+LL | m!(generic<p!()>);
+   |           ^^^^^^
+
+error: cannot find attribute `generic` in this scope
+  --> $DIR/macro-expand-within-generics-in-path.rs:15:4
+   |
+LL | m!(generic<p!()>);
+   |    ^^^^^^^
+
+error: aborting due to 2 previous errors
+

tests/ui/span/macro-ty-params.rs

@@ -11,5 +11,4 @@ fn main() {
     foo::<>!(); //~ ERROR generic arguments in macro path
     m!(Default<>);
     //~^ ERROR unexpected generic arguments in path
-    //~^^ ERROR generic arguments in macro path
 }

tests/ui/span/macro-ty-params.stderr

@@ -16,11 +16,5 @@ error: unexpected generic arguments in path
 LL |     m!(Default<>);
    |               ^^
 
-error: generic arguments in macro path
-  --> $DIR/macro-ty-params.rs:12:15
-   |
-LL |     m!(Default<>);
-   |               ^^
-
-error: aborting due to 4 previous errors
+error: aborting due to 3 previous errors