create localdecl and add span to it

compiler/rustc_smir/src/rustc_smir/mod.rs

@@ -106,7 +106,14 @@ impl<'tcx> Context for Tables<'tcx> {
                         .collect(),
                 })
                 .collect(),
-            locals: mir.local_decls.iter().map(|decl| self.intern_ty(decl.ty)).collect(),
+            locals: mir
+                .local_decls
+                .iter()
+                .map(|decl| stable_mir::mir::LocalDecl {
+                    ty: self.intern_ty(decl.ty),
+                    span: decl.source_info.span.stable(self),
+                })
+                .collect(),
         }
     }
 

compiler/stable_mir/src/mir/body.rs

@@ -5,7 +5,13 @@ use crate::{ty::Ty, Span};
 #[derive(Clone, Debug)]
 pub struct Body {
     pub blocks: Vec<BasicBlock>,
-    pub locals: Vec<Ty>,
+    pub locals: Vec<LocalDecl>,
+}
+
+#[derive(Clone, Debug)]
+pub struct LocalDecl {
+    pub ty: Ty,
+    pub span: Span,
 }
 
 #[derive(Clone, Debug)]