diff --git a/clippy_lints/src/escape.rs b/clippy_lints/src/escape.rs
index 2038a5913..d4c91eab1 100644
--- a/clippy_lints/src/escape.rs
+++ b/clippy_lints/src/escape.rs
@@ -5,10 +5,11 @@ use rustc::lint::*;
 use rustc::middle::expr_use_visitor::*;
 use rustc::middle::mem_categorization::{cmt, Categorization};
 use rustc::ty::{self, Ty};
+use rustc::ty::layout::LayoutOf;
 use rustc::util::nodemap::NodeSet;
 use syntax::ast::NodeId;
 use syntax::codemap::Span;
-use utils::{span_lint, type_size};
+use utils::span_lint;
 
 pub struct Pass {
     pub too_large_for_stack: u64,
@@ -164,7 +165,7 @@ impl<'a, 'tcx> EscapeDelegate<'a, 'tcx> {
         // Large types need to be boxed to avoid stack
         // overflows.
         if ty.is_box() {
-            type_size(self.cx, ty.boxed_ty()).unwrap_or(0) > self.too_large_for_stack
+            self.cx.layout_of(ty.boxed_ty()).ok().map_or(0, |l| l.size.bytes()) > self.too_large_for_stack
         } else {
             false
         }
diff --git a/clippy_lints/src/large_enum_variant.rs b/clippy_lints/src/large_enum_variant.rs
index ceb0cbd66..e13b771cf 100644
--- a/clippy_lints/src/large_enum_variant.rs
+++ b/clippy_lints/src/large_enum_variant.rs
@@ -2,8 +2,8 @@
 
 use rustc::lint::*;
 use rustc::hir::*;
-use utils::{snippet_opt, span_lint_and_then, type_size};
-use rustc::ty::TypeFoldable;
+use utils::{snippet_opt, span_lint_and_then};
+use rustc::ty::layout::LayoutOf;
 
 /// **What it does:** Checks for large size differences between variants on
 /// `enum`s.
@@ -61,13 +61,11 @@ impl<'a, 'tcx> LateLintPass<'a, 'tcx> for LargeEnumVariant {
                 let size: u64 = variant
                     .fields
                     .iter()
-                    .map(|f| {
+                    .filter_map(|f| {
                         let ty = cx.tcx.type_of(f.did);
-                        if ty.needs_subst() {
-                            0 // we can't reason about generics, so we treat them as zero sized
-                        } else {
-                            type_size(cx, ty).expect("size should be computable for concrete type")
-                        }
+                        // don't count generics by filtering out everything
+                        // that does not have a layout
+                        cx.layout_of(ty).ok().map(|l| l.size.bytes())
                     })
                     .sum();
 
diff --git a/clippy_lints/src/types.rs b/clippy_lints/src/types.rs
index c7e724625..ba79bf440 100644
--- a/clippy_lints/src/types.rs
+++ b/clippy_lints/src/types.rs
@@ -4,6 +4,7 @@ use rustc::hir::*;
 use rustc::hir::intravisit::{walk_body, walk_expr, walk_ty, FnKind, NestedVisitorMap, Visitor};
 use rustc::lint::*;
 use rustc::ty::{self, Ty, TyCtxt, TypeckTables};
+use rustc::ty::layout::LayoutOf;
 use rustc::ty::subst::Substs;
 use rustc_typeck::hir_ty_to_ty;
 use std::cmp::Ordering;
@@ -15,7 +16,7 @@ use syntax::codemap::Span;
 use syntax::errors::DiagnosticBuilder;
 use utils::{comparisons, higher, in_constant, in_external_macro, in_macro, last_path_segment, match_def_path, match_path,
             multispan_sugg, opt_def_id, same_tys, snippet, snippet_opt, span_help_and_lint, span_lint,
-            span_lint_and_sugg, span_lint_and_then, type_size};
+            span_lint_and_sugg, span_lint_and_then};
 use utils::paths;
 
 /// Handles all the linting of funky types
@@ -1478,7 +1479,7 @@ fn numeric_cast_precast_bounds<'a>(cx: &LateContext, expr: &'a Expr) -> Option<(
         let pre_cast_ty = cx.tables.expr_ty(cast_exp);
         let cast_ty = cx.tables.expr_ty(expr);
         // if it's a cast from i32 to u32 wrapping will invalidate all these checks
-        if type_size(cx, pre_cast_ty) == type_size(cx, cast_ty) {
+        if cx.layout_of(pre_cast_ty).ok().map(|l| l.size) == cx.layout_of(cast_ty).ok().map(|l| l.size) {
             return None;
         }
         match pre_cast_ty.sty {
diff --git a/clippy_lints/src/utils/mod.rs b/clippy_lints/src/utils/mod.rs
index e89163fb5..c501dadeb 100644
--- a/clippy_lints/src/utils/mod.rs
+++ b/clippy_lints/src/utils/mod.rs
@@ -9,7 +9,6 @@ use rustc::lint::{LateContext, Level, Lint, LintContext};
 use rustc::session::Session;
 use rustc::traits;
 use rustc::ty::{self, Ty, TyCtxt};
-use rustc::ty::layout::LayoutOf;
 use rustc_errors;
 use std::borrow::Cow;
 use std::env;
@@ -1048,12 +1047,6 @@ pub fn is_try(expr: &Expr) -> Option<&Expr> {
     None
 }
 
-pub fn type_size<'a, 'tcx>(cx: &LateContext<'a, 'tcx>, ty: Ty<'tcx>) -> Option<u64> {
-    cx.layout_of(ty)
-        .ok()
-        .map(|layout| layout.size.bytes())
-}
-
 /// Returns true if the lint is allowed in the current context
 ///
 /// Useful for skipping long running code when it's unnecessary