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diff --git a/compiler/rustc_error_codes/src/error_codes/E0533.md b/compiler/rustc_error_codes/src/error_codes/E0533.md
new file mode 100644
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+++ b/compiler/rustc_error_codes/src/error_codes/E0533.md
@@ -0,0 +1,34 @@
+An item which isn't a unit struct, a variant, nor a constant has been used as a
+match pattern.
+
+Erroneous code example:
+
+```compile_fail,E0533
+struct Tortoise;
+
+impl Tortoise {
+    fn turtle(&self) -> u32 { 0 }
+}
+
+match 0u32 {
+    Tortoise::turtle => {} // Error!
+    _ => {}
+}
+if let Tortoise::turtle = 0u32 {} // Same error!
+```
+
+If you want to match against a value returned by a method, you need to bind the
+value first:
+
+```
+struct Tortoise;
+
+impl Tortoise {
+    fn turtle(&self) -> u32 { 0 }
+}
+
+match 0u32 {
+    x if x == Tortoise.turtle() => {} // Bound into `x` then we compare it!
+    _ => {}
+}
+```