Specify return type unit fallback

src/expressions.rst

@@ -3568,6 +3568,15 @@ Closure Expressions
 A :t:`closure expression` is an :t:`expression` that defines a
 :t:`closure type` and constructs a value of that :t:`type`.
 
+:dp:`fls_UgJgur0z6d4a`
+The :t:`return type` of a :t:`closure type` is determined as follows:
+
+* :dp:`fls_af1WL2mBKMfW`
+  If the :t:`closure expression` specifies a :s:`ClosureBodyWithReturnType`, then the :t:`return type` is the specified :s:`ReturnTypeWithoutBounds`.
+
+* :dp:`fls_wLVeE6cNG8oa`
+  Otherwise the :t:`return type` is the :t:`type` of the :t:`closure body`.
+
 :dp:`fls_srbl7ptknjyk`
 A :t:`closure body` is a :t:`construct` that represents the executable portion
 of a :t:`closure expression`.

src/functions.rst

@@ -84,7 +84,16 @@ The :t:`pattern` of a :t:`function parameter` shall be an :t:`irrefutable
 pattern`.
 
 :dp:`fls_vljy4mm0zca2`
-A :t:`return type` is the :t:`type` of the result a :t:`function` returns.
+A :t:`return type` is the :t:`type` of the result a :t:`function`, :t:`closure type` or :t:`function pointer type` returns.
+
+:dp:`fls_EqJb3Jl3vK8K`
+The :t:`return type` of a :t:`function` is determined as follows:
+
+* :dp:`fls_C7dvzcXcpQCy`
+  If the :s:`FunctionDeclaration` specifies a :s:`ReturnType`, then the :t:`return type` is the specified :s:`ReturnType`.
+
+* :dp:`fls_J8X8ahnJLrMo`
+  Otherwise the :t:`return type` is the :t:`unit type`.
 
 :dp:`fls_927nfm5mkbsp`
 A :t:`function body` is the :t:`block expression` of a :t:`function`.
@@ -183,4 +192,3 @@ program. A :t:`main function` is subject to the following restrictions:
    }
 
    fn main() {}
-

src/types-and-traits.rst

@@ -971,6 +971,15 @@ parameters.
 A :t:`variadic part` shall be specified only when the :t:`ABI` of the
 :t:`function pointer type` is either ``extern "C"`` or ``extern "cdecl"``.
 
+:dp:`fls_g1iYVw7upBnH`
+The :t:`return type` of a :t:`function pointer type` is determined as follows:
+
+* :dp:`fls_8gpvNJfVlyaD`
+  If the :t:`function pointer type` specifies a :s:`ReturnTypeWithoutBounds`, then the :t:`return type` is the specified :s:`ReturnTypeWithoutBounds`.
+
+* :dp:`fls_KcI6yK0P8Onn`
+  Otherwise the :t:`return type` is the :t:`unit type`.
+
 .. rubric:: Undefined Behavior
 
 :dp:`fls_52thmi9hnoks`