Avoid various uses of Option<Span> in favor of using DUMMY_SP in …

…the few cases that used `None`

src/constant.rs

@@ -74,7 +74,7 @@ pub(crate) fn eval_mir_constant<'tcx>(
     let cv = fx.monomorphize(constant.const_);
     // This cannot fail because we checked all required_consts in advance.
     let val = cv
-        .eval(fx.tcx, ty::ParamEnv::reveal_all(), Some(constant.span))
+        .eval(fx.tcx, ty::ParamEnv::reveal_all(), constant.span)
         .expect("erroneous constant missed by mono item collection");
     (val, cv.ty())
 }

src/intrinsics/mod.rs

@@ -728,8 +728,10 @@ fn codegen_regular_intrinsic_call<'tcx>(
         | sym::variant_count => {
             intrinsic_args!(fx, args => (); intrinsic);
 
-            let const_val =
-                fx.tcx.const_eval_instance(ParamEnv::reveal_all(), instance, None).unwrap();
+            let const_val = fx
+                .tcx
+                .const_eval_instance(ParamEnv::reveal_all(), instance, source_info.span)
+                .unwrap();
             let val = crate::constant::codegen_const_value(fx, const_val, ret.layout().ty);
             ret.write_cvalue(fx, val);
         }

src/intrinsics/simd.rs

@@ -131,7 +131,7 @@ pub(super) fn codegen_simd_intrinsic_call<'tcx>(
 
             let idx = generic_args[2]
                 .expect_const()
-                .eval(fx.tcx, ty::ParamEnv::reveal_all(), Some(span))
+                .eval(fx.tcx, ty::ParamEnv::reveal_all(), span)
                 .unwrap()
                 .unwrap_branch();