gccrs: fix bad type inference on local patterns

We do not need to inject inference variables on generic patterns
with generic blocks. This will just cause unconstrained inference
variables as they may not unify against something.

Fixes Rust-GCC#2323

gcc/rust/ChangeLog:

	* typecheck/rust-hir-type-check-path.cc (TypeCheckExpr::resolve_root_path): dont infer here

gcc/testsuite/ChangeLog:

	* rust/compile/nr2/exclude: nr2 cant handle this
	* rust/compile/issue-2323.rs: New test.

Signed-off-by: Philip Herron <herron.philip@googlemail.com>

diff --git a/gcc/rust/typecheck/rust-hir-type-check-path.cc b/gcc/rust/typecheck/rust-hir-type-check-path.cc
index 231ddd604db2289132ec7aa016752ce2a1639222..7b934b38eb37a62c4717ed4d58af17b454ec2580 100644 (file)
--- a/gcc/rust/typecheck/rust-hir-type-check-path.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-path.cc
@@ -245,6 +245,7 @@ TypeCheckExpr::resolve_root_path (HIR::PathInExpression &expr, size_t *offset,
 
       auto seg_is_module = mappings.lookup_module (ref).has_value ();
       auto seg_is_crate = mappings.is_local_hirid_crate (ref);
+      auto seg_is_pattern = mappings.lookup_hir_pattern (ref).has_value ();
       if (seg_is_module || seg_is_crate)
        {
          // A::B::C::this_is_a_module::D::E::F
@@ -321,7 +322,7 @@ TypeCheckExpr::resolve_root_path (HIR::PathInExpression &expr, size_t *offset,
          if (lookup->get_kind () == TyTy::TypeKind::ERROR)
            return new TyTy::ErrorType (expr.get_mappings ().get_hirid ());
        }
-      else if (lookup->needs_generic_substitutions ())
+      else if (lookup->needs_generic_substitutions () && !seg_is_pattern)
        {
          lookup = SubstMapper::InferSubst (lookup, expr.get_locus ());
        }

diff --git a/gcc/testsuite/rust/compile/issue-2323.rs b/gcc/testsuite/rust/compile/issue-2323.rs
new file mode 100644 (file)
index 0000000..02a3f90
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-2323.rs
@@ -0,0 +1,9 @@
+#[lang = "sized"]
+trait Sized {}
+
+pub struct S<T>(T);
+
+pub fn foo<T>(x: T) {
+    let y = S(x);
+    y.0;
+}

diff --git a/gcc/testsuite/rust/compile/nr2/exclude b/gcc/testsuite/rust/compile/nr2/exclude
index 4ba27d31f88b3492c82721c3b88b0158165e7453..eaa2a1e0d0bc2c5d743a5cd01f4b9258947ade9d 100644 (file)
--- a/gcc/testsuite/rust/compile/nr2/exclude
+++ b/gcc/testsuite/rust/compile/nr2/exclude
@@ -222,4 +222,5 @@ if_let_expr_simple.rs
 iflet.rs
 issue-3033.rs
 issue-3009.rs
+issue-2323.rs
 # please don't delete the trailing newline