Remove unused variable assignments

Multiple local variables were not read beyond their assignments.

gcc/rust/ChangeLog:

	* typecheck/rust-hir-type-check-expr.cc (TypeCheckExpr::visit): Remove
	unused assignment.
	* typecheck/rust-hir-type-check-path.cc (TypeCheckExpr::resolve_segments):
	Likewise.
	* typecheck/rust-tyty.cc (ParamType::handle_substitions): Likewise.
	* typecheck/rust-unify.cc (UnifyRules::go): Likewise.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

Author: P-E-P

gcc/rust/typecheck/rust-hir-type-check-expr.cc

@@ -629,10 +629,9 @@ TypeCheckExpr::visit (HIR::BlockExpr &expr)
       if (s->is_unit_check_needed () && !resolved->is_unit ())
 	{
 	  auto unit = TyTy::TupleType::get_unit_type ();
-	  resolved
-	    = unify_site (s->get_mappings ().get_hirid (),
-			  TyTy::TyWithLocation (unit),
-			  TyTy::TyWithLocation (resolved), s->get_locus ());
+	  unify_site (s->get_mappings ().get_hirid (),
+		      TyTy::TyWithLocation (unit),
+		      TyTy::TyWithLocation (resolved), s->get_locus ());
 	}
     }
 

gcc/rust/typecheck/rust-hir-type-check-path.cc

@@ -517,9 +517,8 @@ TypeCheckExpr::resolve_segments (NodeId root_resolved_node_id,
 	      const auto &predicate
 		= impl_block_ty->lookup_predicate (trait_ref.get_defid ());
 	      if (!predicate.is_error ())
-		impl_block_ty
-		  = associated->setup_associated_types (prev_segment, predicate,
-							nullptr, false);
+		associated->setup_associated_types (prev_segment, predicate,
+						    nullptr, false);
 	    }
 	}
 

gcc/rust/typecheck/rust-tyty.cc

@@ -3566,7 +3566,7 @@ ParamType::handle_substitions (SubstitutionArgumentMappings &subst_mappings)
     {
       const ParamType &pp = *static_cast<const ParamType *> (resolved);
       if (pp.can_resolve ())
-	resolved = pp.resolve ();
+	pp.resolve ();
     }
 
   // this is the new subst that this needs to pass

gcc/rust/typecheck/rust-unify.cc

@@ -155,11 +155,8 @@ UnifyRules::emit_abi_mismatch (const TyTy::FnType &expected,
 TyTy::BaseType *
 UnifyRules::go ()
 {
-  TyTy::BaseType *ltype = lhs.get_ty ();
-  TyTy::BaseType *rtype = rhs.get_ty ();
-
-  ltype = lhs.get_ty ()->destructure ();
-  rtype = rhs.get_ty ()->destructure ();
+  TyTy::BaseType *ltype = lhs.get_ty ()->destructure ();
+  TyTy::BaseType *rtype = rhs.get_ty ()->destructure ();
 
   rust_debug ("unify::go ltype={%s} rtype={%s}", ltype->debug_str ().c_str (),
 	      rtype->debug_str ().c_str ());