[analyzer][NFC] Eliminate a dyn_cast (llvm#100719)

Response to the catch in this comment:
https://github.com/llvm/llvm-project/pull/94357/files/07f6daf2cf0f5d5bd4fc9950f2585a3f52b4ad2f#r1692084074

Author: Szelethus

clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp

@@ -832,9 +832,18 @@ class NoMemOwnershipChangeVisitor final : public NoOwnershipChangeVisitor {
   /// information.
   bool doesFnIntendToHandleOwnership(const Decl *Callee,
                                      ASTContext &ACtx) final {
-    using namespace clang::ast_matchers;
     const FunctionDecl *FD = dyn_cast<FunctionDecl>(Callee);
 
+    // Given that the stack frame was entered, the body should always be
+    // theoretically obtainable. In case of body farms, the synthesized body
+    // is not attached to declaration, thus triggering the '!FD->hasBody()'
+    // branch. That said, would a synthesized body ever intend to handle
+    // ownership? As of today they don't. And if they did, how would we
+    // put notes inside it, given that it doesn't match any source locations?
+    if (!FD || !FD->hasBody())
+      return false;
+    using namespace clang::ast_matchers;
+
     auto Matches = match(findAll(stmt(anyOf(cxxDeleteExpr().bind("delete"),
                                             callExpr().bind("call")))),
                          *FD->getBody(), ACtx);

clang/lib/StaticAnalyzer/Checkers/NoOwnershipChangeVisitor.cpp

@@ -72,16 +72,6 @@ bool NoOwnershipChangeVisitor::wasModifiedInFunction(
     const ExplodedNode *CallEnterN, const ExplodedNode *CallExitEndN) {
   const Decl *Callee =
       CallExitEndN->getFirstPred()->getLocationContext()->getDecl();
-  const FunctionDecl *FD = dyn_cast<FunctionDecl>(Callee);
-
-  // Given that the stack frame was entered, the body should always be
-  // theoretically obtainable. In case of body farms, the synthesized body
-  // is not attached to declaration, thus triggering the '!FD->hasBody()'
-  // branch. That said, would a synthesized body ever intend to handle
-  // ownership? As of today they don't. And if they did, how would we
-  // put notes inside it, given that it doesn't match any source locations?
-  if (!FD || !FD->hasBody())
-    return false;
   if (!doesFnIntendToHandleOwnership(
           Callee,
           CallExitEndN->getState()->getAnalysisManager().getASTContext()))

clang/lib/StaticAnalyzer/Checkers/StreamChecker.cpp

@@ -755,9 +755,18 @@ class NoStreamStateChangeVisitor final : public NoOwnershipChangeVisitor {
 
   bool doesFnIntendToHandleOwnership(const Decl *Callee,
                                      ASTContext &ACtx) final {
-    using namespace clang::ast_matchers;
     const FunctionDecl *FD = dyn_cast<FunctionDecl>(Callee);
 
+    // Given that the stack frame was entered, the body should always be
+    // theoretically obtainable. In case of body farms, the synthesized body
+    // is not attached to declaration, thus triggering the '!FD->hasBody()'
+    // branch. That said, would a synthesized body ever intend to handle
+    // ownership? As of today they don't. And if they did, how would we
+    // put notes inside it, given that it doesn't match any source locations?
+    if (!FD || !FD->hasBody())
+      return false;
+    using namespace clang::ast_matchers;
+
     auto Matches =
         match(findAll(callExpr().bind("call")), *FD->getBody(), ACtx);
     for (BoundNodes Match : Matches) {