merge unsafe-block and unsafe-function into one page

Author: RalfJung

book.toml

@@ -10,6 +10,8 @@ edit-url-template = "https://github.com/rust-lang/reference/edit/master/{path}"
 
 [output.html.redirect]
 "/expressions/enum-variant-expr.html" = "struct-expr.html"
+"/unsafe-blocks.html" = "unsafe-keyword.html"
+"/unsafe-functions.html" = "unsafe-keyword.html"
 
 [rust]
 edition = "2021"

src/SUMMARY.md

@@ -118,8 +118,7 @@
 - [Inline assembly](inline-assembly.md)
 
 - [Unsafety](unsafety.md)
-    - [Unsafe functions](unsafe-functions.md)
-    - [Unsafe blocks](unsafe-blocks.md)
+    - [The `unsafe` keyword](unsafe-keyword.md)
     - [Behavior considered undefined](behavior-considered-undefined.md)
     - [Behavior not considered unsafe](behavior-not-considered-unsafe.md)
 

src/attributes/codegen.md

@@ -347,7 +347,7 @@ trait object whose methods are attributed.
 [target architecture]: ../conditional-compilation.md#target_arch
 [trait]: ../items/traits.md
 [undefined behavior]: ../behavior-considered-undefined.md
-[unsafe function]: ../unsafe-functions.md
+[unsafe function]: ../unsafe-keyword.md
 [rust-abi]: ../items/external-blocks.md#abi
 [`core::intrinsics::caller_location`]: ../../core/intrinsics/fn.caller_location.html
 [`core::panic::Location::caller`]: ../../core/panic/struct.Location.html#method.caller

src/types/function-pointer.md

@@ -62,5 +62,5 @@ restrictions as [regular function parameters].
 [closures]: closure.md
 [extern function]: ../items/functions.md#extern-function-qualifier
 [function items]: function-item.md
-[unsafe function]: ../unsafe-functions.md
+[unsafe function]: ../unsafe-keyword.md
 [regular function parameters]: ../items/functions.md#attributes-on-function-parameters

src/unsafe-functions.md

@@ -1,4 +1,12 @@
-# Unsafe blocks
+# The `unsafe` keyword
+
+## Unsafe functions
+
+Unsafe functions are functions that are not safe in all contexts and/or for all
+possible inputs. Such a function must be prefixed with the keyword `unsafe` and
+can only be called from an `unsafe` block or another `unsafe` function.
+
+## Unsafe blocks
 
 A block of code can be prefixed with the `unsafe` keyword, to permit calling
 `unsafe` functions or dereferencing raw pointers within a safe function.