const-eval.const-expr.borrows: mention indirect places

src/const_eval.md

@@ -83,9 +83,12 @@ r[const-eval.const-expr.builtin-arith-logic]
 r[const-eval.const-expr.borrows]
 * All forms of [borrow]s, including raw borrows, with one limitation:
   mutable borrows and shared borrows to values with interior mutability
-  are only allowed to refer to *transient* places or to *static* places. A place is *transient*
-  if its lifetime is strictly contained inside the current [const context].
-  A place is *static* if it is a `static` item or a [promoted expression].
+  are not allowed to refer to [lifetime-extended temporaries in the top-level scope of a `const` or `static` initializer expression][lifetime-extension-const].
+
+  In other words, they are only allowed to refer to *transient* places, to *indirect* places, or to *static* places.
+  A place is *transient* if it is based on a local variable whose lifetime is strictly contained inside the current [const context].
+  A place is *indirect* if it is based on a [dereference expression][dereference operator].
+  A place is *static* if it is based on a `static` item or a [promoted expression].
 
 r[const-eval.const-expr.deref]
 * The [dereference operator] except for raw pointers.
@@ -187,6 +190,7 @@ of whether you are building on a `64` bit or a `32` bit system.
 [interior mutability]:  interior-mutability.md
 [if]:                   expressions/if-expr.md#if-expressions
 [lazy boolean]:         expressions/operator-expr.md#lazy-boolean-operators
+[lifetime-extension-const]: destructors.md#r-destructors.scope.lifetime-extension.static
 [let statements]:       statements.md#let-statements
 [literals]:             expressions/literal-expr.md
 [logical]:              expressions/operator-expr.md#arithmetic-and-logical-binary-operators

src/destructors.md

@@ -336,8 +336,9 @@ println!("{}", x);
 ```
 
 r[destructors.scope.lifetime-extension.static]
-Lifetime extension also applies to `static` and `const` items, where it
-makes temporaries live until the end of the program. For example:
+Lifetime extension also applies to the top-level scope of `static` and `const` items,
+where it makes temporaries live until the end of the program.
+For example:
 
 ```rust
 const C: &Vec<i32> = &Vec::new();