Minimize visibilities.

This makes it much clearer which things are used outside the crate.

compiler/rustc_codegen_ssa/src/mir/statement.rs

@@ -7,7 +7,7 @@ use crate::traits::*;
 
 impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
     #[instrument(level = "debug", skip(self, bx))]
-    pub fn codegen_statement(&mut self, bx: &mut Bx, statement: &mir::Statement<'tcx>) {
+    pub(crate) fn codegen_statement(&mut self, bx: &mut Bx, statement: &mir::Statement<'tcx>) {
         self.set_debug_loc(bx, statement.source_info);
         match statement.kind {
             mir::StatementKind::Assign(box (ref place, ref rvalue)) => {