From bbee3c44e9236ca823c1c85ebd03087f78d29656 Mon Sep 17 00:00:00 2001
From: Jen Downs <hello@jendowns.com>
Date: Mon, 23 Dec 2019 16:29:19 -0600
Subject: [PATCH] fix(styles): add error handling for rem & em sass functions
 (#4931)

---
 packages/components/src/globals/scss/_typography.scss | 10 ++++++++++
 packages/layout/scss/_convert.scss                    | 10 ++++++++++
 2 files changed, 20 insertions(+)

diff --git a/packages/components/src/globals/scss/_typography.scss b/packages/components/src/globals/scss/_typography.scss
index ad3932a18345..a1bcf9ea28d3 100644
--- a/packages/components/src/globals/scss/_typography.scss
+++ b/packages/components/src/globals/scss/_typography.scss
@@ -22,6 +22,11 @@ $base-font-size: 16px !default;
 /// @group global-typography
 /// @deprecated (For v10) Use `carbon--rem()`
 @function rem($px) {
+  @if unit($px) != 'px' {
+    // TODO: update to @error in v11
+    @warn "Expected argument $px to be of type `px`, instead received: `#{unit($px)}`";
+  }
+
   @return ($px / $base-font-size) * 1rem;
 }
 
@@ -33,6 +38,11 @@ $base-font-size: 16px !default;
 /// @group global-typography
 /// @deprecated (For v10) Use `carbon--em()`
 @function em($px) {
+  @if unit($px) != 'px' {
+    // TODO: update to @error in v11
+    @warn "Expected argument $px to be of type `px`, instead received: `#{unit($px)}`";
+  }
+
   @return ($px / $base-font-size) * 1em;
 }
 
diff --git a/packages/layout/scss/_convert.scss b/packages/layout/scss/_convert.scss
index 339fc78e5257..7c5f5d98a69d 100644
--- a/packages/layout/scss/_convert.scss
+++ b/packages/layout/scss/_convert.scss
@@ -17,6 +17,11 @@ $carbon--base-font-size: 16px !default;
 /// @access public
 /// @group @carbon/layout
 @function carbon--rem($px) {
+  @if unit($px) != 'px' {
+    // TODO: update to @error in v11
+    @warn "Expected argument $px to be of type `px`, instead received: `#{unit($px)}`";
+  }
+
   @return ($px / $carbon--base-font-size) * 1rem;
 }
 
@@ -26,5 +31,10 @@ $carbon--base-font-size: 16px !default;
 /// @access public
 /// @group @carbon/layout
 @function carbon--em($px) {
+  @if unit($px) != 'px' {
+    // TODO: update to @error in v11
+    @warn "Expected argument $px to be of type `px`, instead received: `#{unit($px)}`";
+  }
+
   @return ($px / $carbon--base-font-size) * 1em;
 }