[Clang] Fix looking for immediate calls in default arguments.

Due to improper use of RecursiveASTVisitor.

Fixes #80630

Author: cor3ntin

clang/docs/ReleaseNotes.rst

@@ -265,6 +265,8 @@ Bug Fixes to C++ Support
 - No longer reject valid use of the ``_Alignas`` specifier when declaring a
   local variable, which is supported as a C11 extension in C++. Previously, it
   was only accepted at namespace scope but not at local function scope.
+- Fix evaluation of some immediate calls in default arguments.
+  Fixes (`#80630 <https://github.com/llvm/llvm-project/issues/80630>`_)
 
 Bug Fixes to AST Handling
 ^^^^^^^^^^^^^^^^^^^^^^^^^

clang/lib/Sema/SemaExpr.cpp

@@ -6198,7 +6198,7 @@ struct ImmediateCallVisitor : public RecursiveASTVisitor<ImmediateCallVisitor> {
   bool VisitCallExpr(CallExpr *E) {
     if (const FunctionDecl *FD = E->getDirectCallee())
       HasImmediateCalls |= FD->isImmediateFunction();
-    return RecursiveASTVisitor<ImmediateCallVisitor>::VisitStmt(E);
+    return RecursiveASTVisitor<ImmediateCallVisitor>::VisitCallExpr(E);
   }
 
   // SourceLocExpr are not immediate invocations
@@ -6222,9 +6222,9 @@ struct ImmediateCallVisitor : public RecursiveASTVisitor<ImmediateCallVisitor> {
 
   // Blocks don't support default parameters, and, as for lambdas,
   // we don't consider their body a subexpression.
-  bool VisitBlockDecl(BlockDecl *B) { return false; }
+  bool VisitBlockDecl(BlockDecl *B) { return true; }
 
-  bool VisitCompoundStmt(CompoundStmt *B) { return false; }
+  bool VisitCompoundStmt(CompoundStmt *B) { return true; }
 
   bool VisitCXXDefaultArgExpr(CXXDefaultArgExpr *E) {
     return TraverseStmt(E->getExpr());

clang/test/SemaCXX/cxx2a-consteval-default-params.cpp

@@ -82,3 +82,18 @@ namespace GH62224 {
   C<> Val; // No error since fwd is defined already.
   static_assert(Val.get() == 42);
 }
+
+namespace GH80630 {
+
+consteval const char* ce() { return "Hello"; }
+
+auto f2(const char* loc = []( char const* fn )
+    { return fn; }  ( ce() ) ) {
+    return loc;
+}
+
+auto g() {
+    return f2();
+}
+
+}

clang/test/SemaCXX/source_location.cpp

@@ -832,3 +832,21 @@ void test() {
 }
 
 }
+
+namespace GH80630 {
+
+#define GH80630_LAMBDA \
+    []( char const* fn ) { \
+        static constexpr std::source_location loc = std::source_location::current(); \
+        return &loc; \
+    }( std::source_location::current().function() )
+
+auto f( std::source_location const* loc = GH80630_LAMBDA ) {
+    return loc;
+}
+
+auto g() {
+    return f();
+}
+
+}