UPDATE - migrate constant.rs to new diagnostics infrastructure

Author: JhonnyBillM

compiler/rustc_codegen_ssa/src/errors.rs

@@ -554,3 +554,17 @@ pub struct MetadataObjectFileWrite {
 pub struct InvalidWindowsSubsystem {
     pub subsystem: Symbol,
 }
+
+#[derive(Diagnostic)]
+#[diag(codegen_ssa_erroneous_constant)]
+pub struct ErroneousConstant {
+    #[primary_span]
+    pub span: Span,
+}
+
+#[derive(Diagnostic)]
+#[diag(codegen_ssa_shuffle_indices_evaluation)]
+pub struct ShuffleIndicesEvaluation {
+    #[primary_span]
+    pub span: Span,
+}

compiler/rustc_codegen_ssa/src/mir/constant.rs

@@ -1,3 +1,4 @@
+use crate::errors;
 use crate::mir::operand::OperandRef;
 use crate::traits::*;
 use rustc_middle::mir;
@@ -42,7 +43,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
         };
 
         self.cx.tcx().const_eval_resolve(ty::ParamEnv::reveal_all(), uv, None).map_err(|err| {
-            self.cx.tcx().sess.span_err(constant.span, "erroneous constant encountered");
+            self.cx.tcx().sess.emit_err(errors::ErroneousConstant { span: constant.span });
             err
         })
     }
@@ -80,7 +81,7 @@ impl<'a, 'tcx, Bx: BuilderMethods<'a, 'tcx>> FunctionCx<'a, 'tcx, Bx> {
                 (llval, c.ty())
             })
             .unwrap_or_else(|_| {
-                bx.tcx().sess.span_err(span, "could not evaluate shuffle_indices at compile time");
+                bx.tcx().sess.emit_err(errors::ShuffleIndicesEvaluation { span });
                 // We've errored, so we don't have to produce working code.
                 let ty = self.monomorphize(ty);
                 let llty = bx.backend_type(bx.layout_of(ty));

compiler/rustc_error_messages/locales/en-US/codegen_ssa.ftl

@@ -193,3 +193,7 @@ codegen_ssa_multiple_main_functions = entry symbol `main` declared multiple time
 codegen_ssa_metadata_object_file_write = error writing metadata object file: {$error}
 
 codegen_ssa_invalid_windows_subsystem = invalid windows subsystem `{$subsystem}`, only `windows` and `console` are allowed
+
+codegen_ssa_erroneous_constant = erroneous constant encountered
+
+codegen_ssa_shuffle_indices_evaluation = could not evaluate shuffle_indices at compile time