[gcc r16-217] gccrs: Fix ICE with empty generic arguments

[Arthur Cohen via Gcc-cvs]

https://gcc.gnu.org/g:efb94eb85d2382c795fa7b69feeb5425590519dc

commit r16-217-gefb94eb85d2382c795fa7b69feeb5425590519dc
Author: Philip Herron <herron.phi...@googlemail.com>
Date:   Thu Apr 17 15:53:58 2025 +0100

    gccrs: Fix ICE with empty generic arguments
    
    We have an assertion when accessing generic args if there are any which
    is really useful so this adds the missing guards for the case where
    they are specified but empty.
    
    Fixes Rust-GCC#3649
    
    gcc/rust/ChangeLog:
    
            * ast/rust-ast-visitor.cc (DefaultASTVisitor::visit): add guard
            * expand/rust-expand-visitor.cc (ExpandVisitor::visit): add guard
    
    gcc/testsuite/ChangeLog:
    
            * rust/compile/nr2/exclude: nr2 is missing error for this
            * rust/compile/issue-3649.rs: New test.
    
    Signed-off-by: Philip Herron <herron.phi...@googlemail.com>

Diff:
---
 gcc/rust/ast/rust-ast-visitor.cc         | 3 ++-
 gcc/rust/expand/rust-expand-visitor.cc   | 3 ++-
 gcc/testsuite/rust/compile/issue-3649.rs | 2 ++
 gcc/testsuite/rust/compile/nr2/exclude   | 1 +
 4 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/gcc/rust/ast/rust-ast-visitor.cc b/gcc/rust/ast/rust-ast-visitor.cc
index de01a6d3531e..61a3b8b4bf77 100644
--- a/gcc/rust/ast/rust-ast-visitor.cc
+++ b/gcc/rust/ast/rust-ast-visitor.cc
@@ -108,7 +108,8 @@ DefaultASTVisitor::visit (GenericArgsBinding &binding)
 void
 DefaultASTVisitor::visit (AST::TypePathSegmentGeneric &segment)
 {
-  visit (segment.get_generic_args ());
+  if (segment.has_generic_args ())
+    visit (segment.get_generic_args ());
 }
 
 void
diff --git a/gcc/rust/expand/rust-expand-visitor.cc 
b/gcc/rust/expand/rust-expand-visitor.cc
index d4db3137565e..42df5e1ee118 100644
--- a/gcc/rust/expand/rust-expand-visitor.cc
+++ b/gcc/rust/expand/rust-expand-visitor.cc
@@ -489,7 +489,8 @@ ExpandVisitor::visit (AST::PathInExpression &path)
 void
 ExpandVisitor::visit (AST::TypePathSegmentGeneric &segment)
 {
-  expand_generic_args (segment.get_generic_args ());
+  if (segment.has_generic_args ())
+    expand_generic_args (segment.get_generic_args ());
 }
 
 void
diff --git a/gcc/testsuite/rust/compile/issue-3649.rs 
b/gcc/testsuite/rust/compile/issue-3649.rs
new file mode 100644
index 000000000000..b85b193312ef
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-3649.rs
@@ -0,0 +1,2 @@
+struct T(Box<>);
+// { dg-error "could not resolve type path .Box. .E0412." "" { target *-*-* } 
.-1 }
diff --git a/gcc/testsuite/rust/compile/nr2/exclude 
b/gcc/testsuite/rust/compile/nr2/exclude
index e5911b2a6ac0..12e63d884a38 100644
--- a/gcc/testsuite/rust/compile/nr2/exclude
+++ b/gcc/testsuite/rust/compile/nr2/exclude
@@ -22,4 +22,5 @@ issue-3568.rs
 issue-3663.rs
 issue-3671.rs
 issue-3652.rs
+issue-3649.rs
 # please don't delete the trailing newline