Point to local place span on "type too big" error

src/librustc_codegen_llvm/builder.rs

@@ -6,6 +6,7 @@ use crate::type_::Type;
 use crate::type_of::LayoutLlvmExt;
 use crate::value::Value;
 use syntax::symbol::LocalInternedString;
+use syntax::source_map::Span;
 use rustc_codegen_ssa::common::{IntPredicate, TypeKind, RealPredicate};
 use rustc_codegen_ssa::MemFlags;
 use libc::{c_uint, c_char};
@@ -90,6 +91,9 @@ impl ty::layout::LayoutOf for Builder<'_, '_, 'tcx> {
     fn layout_of(&self, ty: Ty<'tcx>) -> Self::TyLayout {
         self.cx.layout_of(ty)
     }
+    fn spanned_layout_of(&self, ty: Ty<'tcx>, _: Option<Span>) -> Self::TyLayout {
+        self.cx.layout_of(ty)
+    }
 }
 
 impl Deref for Builder<'_, 'll, 'tcx> {

src/librustc_codegen_llvm/context.rs

@@ -30,6 +30,7 @@ use std::iter;
 use std::str;
 use std::sync::Arc;
 use syntax::symbol::LocalInternedString;
+use syntax::source_map::Span;
 use crate::abi::Abi;
 
 /// There is one `CodegenCx` per compilation unit. Each one has its own LLVM
@@ -860,9 +861,16 @@ impl LayoutOf for CodegenCx<'ll, 'tcx> {
     type TyLayout = TyLayout<'tcx>;
 
     fn layout_of(&self, ty: Ty<'tcx>) -> Self::TyLayout {
+        self.spanned_layout_of(ty, None)
+    }
+
+    fn spanned_layout_of(&self, ty: Ty<'tcx>, span: Option<Span>) -> Self::TyLayout {
         self.tcx.layout_of(ty::ParamEnv::reveal_all().and(ty))
             .unwrap_or_else(|e| if let LayoutError::SizeOverflow(_) = e {
-                self.sess().fatal(&e.to_string())
+                match span {
+                    Some(span) => self.sess().span_fatal(span, &e.to_string()),
+                    None => self.sess().fatal(&e.to_string()),
+                }
             } else {
                 bug!("failed to get layout for `{}`: {}", ty, e)
             })