SFINAE return type constraints

#feat

Author: alandefreitas

src/lib/AST/ASTVisitor.cpp

@@ -872,6 +872,20 @@ populate(
     }
     else
     {
+        // Return type SFINAE constraints
+        if (I.ReturnType &&
+            !I.ReturnType->Constraints.empty())
+        {
+            for (ExprInfo const& constraint: I.ReturnType->Constraints)
+            {
+                if (!I.Requires.Written.empty())
+                {
+                    I.Requires.Written += " && ";
+                }
+                I.Requires.Written += constraint.Written;
+            }
+        }
+
         // Iterate I.Params to find trailing requires clauses
         for (auto it = I.Params.begin(); it != I.Params.end(); )
         {

test-files/golden-tests/core/libcxx.adoc

@@ -31,7 +31,8 @@ Declared in `<libcxx.cpp>`
 ----
 template<typename T>
 T
-sqrt(T value);
+sqrt(T value)
+requires std::is_integral_v<T>;
 ----
 
 === Description

test-files/golden-tests/core/libcxx.html

@@ -41,7 +41,8 @@ <h3>Synopsis</h3>
 <code class="source-code cpp">
 template&lt;typename T&gt;
 T
-sqrt(T value);
+sqrt(T value)
+requires std::is_integral_v&lt;T&gt;;
 </code>
 </pre>
 </div>

test-files/golden-tests/core/libcxx.xml

@@ -4,7 +4,7 @@
 <namespace id="//////////////////////////8=">
   <template>
     <tparam name="T" class="type"/>
-    <function name="sqrt" id="ulFDUE1svTCX8fV/h8EIp4NNbWs=">
+    <function name="sqrt" requires="std::is_integral_v&lt;T&gt;" id="ulFDUE1svTCX8fV/h8EIp4NNbWs=">
       <file short-path="libcxx.cpp" source-path="libcxx.cpp" line="149"/>
       <return>
         <type name="T"/>

test-files/golden-tests/metadata/sfinae.adoc

@@ -246,7 +246,8 @@ Declared in `<sfinae.cpp>`
 ----
 template<class T>
 T
-f1(T value);
+f1(T value)
+requires std::is_integral_v<T>;
 ----
 
 [#f10]
@@ -294,7 +295,8 @@ Declared in `<sfinae.cpp>`
 ----
 template<class T>
 int
-f2(T value);
+f2(T value)
+requires std::is_integral_v<T>;
 ----
 
 [#f3]
@@ -312,7 +314,8 @@ Declared in `<sfinae.cpp>`
 ----
 template<class T>
 <<B,B>>::<<B-C,C>>
-f3(T value);
+f3(T value)
+requires std&colon;&colon;is&lowbar;integral&lowbar;v&lt;T&gt;;
 ----
 
 [#f4]
@@ -330,7 +333,8 @@ Declared in `&lt;sfinae&period;cpp&gt;`
 ----
 template&lt;class T&gt;
 T
-f4(T value);
+f4(T value)
+requires std&colon;&colon;is&lowbar;integral&lowbar;v&lt;T&gt;;
 ----
 
 [#f5]

test-files/golden-tests/metadata/sfinae.html

@@ -290,7 +290,8 @@ <h3>Synopsis</h3>
 <code class="source-code cpp">
 template&lt;class T&gt;
 T
-f1(T value);
+f1(T value)
+requires std::is_integral_v&lt;T&gt;;
 </code>
 </pre>
 </div>
@@ -343,7 +344,8 @@ <h3>Synopsis</h3>
 <code class="source-code cpp">
 template&lt;class T&gt;
 int
-f2(T value);
+f2(T value)
+requires std::is_integral_v&lt;T&gt;;
 </code>
 </pre>
 </div>
@@ -365,7 +367,8 @@ <h3>Synopsis</h3>
 <code class="source-code cpp">
 template&lt;class T&gt;
 <a href="#B">B</a>::<a href="#B-C">C</a>
-f3(T value);
+f3(T value)
+requires std::is_integral_v&lt;T&gt;;
 </code>
 </pre>
 </div>
@@ -387,7 +390,8 @@ <h3>Synopsis</h3>
 <code class="source-code cpp">
 template&lt;class T&gt;
 T
-f4(T value);
+f4(T value)
+requires std::is_integral_v&lt;T&gt;;
 </code>
 </pre>
 </div>

test-files/golden-tests/metadata/sfinae.xml

@@ -4,7 +4,7 @@
 <namespace id="//////////////////////////8=">
   <template>
     <tparam name="T" class="type"/>
-    <function name="f1" id="Bs19YS1cqZhrsbv149xgnjRFUAk=">
+    <function name="f1" requires="std::is_integral_v&lt;T&gt;" id="Bs19YS1cqZhrsbv149xgnjRFUAk=">
       <file short-path="sfinae.cpp" source-path="sfinae.cpp" line="5"/>
       <return>
         <type name="T"/>
@@ -21,7 +21,7 @@
   </template>
   <template>
     <tparam name="T" class="type"/>
-    <function name="f2" id="uckUKgu5WdbIitoodkl2kXQ7RWI=">
+    <function name="f2" requires="std::is_integral_v&lt;T&gt;" id="uckUKgu5WdbIitoodkl2kXQ7RWI=">
       <file short-path="sfinae.cpp" source-path="sfinae.cpp" line="10"/>
       <return>
         <type name="int"/>
@@ -43,7 +43,7 @@
   </namespace>
   <template>
     <tparam name="T" class="type"/>
-    <function name="f3" id="HIZ4NeNKvHJFhj0tJIjpjaLL30U=">
+    <function name="f3" requires="std::is_integral_v&lt;T&gt;" id="HIZ4NeNKvHJFhj0tJIjpjaLL30U=">
       <file short-path="sfinae.cpp" source-path="sfinae.cpp" line="19"/>
       <return>
         <type id="r/5vKTgl4cXSK5TnuZ/+P7qmkJ0=" name="B::C"/>
@@ -60,7 +60,7 @@
   </template>
   <template>
     <tparam name="T" class="type"/>
-    <function name="f4" id="45LJB0/nCsN3KRlVtnRqNrJG818=">
+    <function name="f4" requires="std::is_integral_v&lt;T&gt;" id="45LJB0/nCsN3KRlVtnRqNrJG818=">
       <file short-path="sfinae.cpp" source-path="sfinae.cpp" line="24"/>
       <return>
         <type name="T"/>

test-files/golden-tests/snippets/sqrt.adoc

@@ -31,7 +31,8 @@ Declared in `<sqrt.cpp>`
 ----
 template<typename T>
 T
-sqrt(T value);
+sqrt(T value)
+requires std::is_integral_v<T>;
 ----
 
 === Description

test-files/golden-tests/snippets/sqrt.html

@@ -41,7 +41,8 @@ <h3>Synopsis</h3>
 <code class="source-code cpp">
 template&lt;typename T&gt;
 T
-sqrt(T value);
+sqrt(T value)
+requires std::is_integral_v&lt;T&gt;;
 </code>
 </pre>
 </div>

test-files/golden-tests/snippets/sqrt.xml

@@ -4,7 +4,7 @@
 <namespace id="//////////////////////////8=">
   <template>
     <tparam name="T" class="type"/>
-    <function name="sqrt" id="ulFDUE1svTCX8fV/h8EIp4NNbWs=">
+    <function name="sqrt" requires="std::is_integral_v&lt;T&gt;" id="ulFDUE1svTCX8fV/h8EIp4NNbWs=">
       <file short-path="sqrt.cpp" source-path="sqrt.cpp" line="15" class="def"/>
       <return>
         <type name="T"/>