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 <[email protected]>
CohenArthur · Nov 4, 2024 · d76edc3 · d76edc3
1 parent efcf4d4
commit d76edc3
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Showing 3 changed files with 12 additions and 1 deletion.
diff --git 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
@@ -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
@@ -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