[PATCH] D34096: [Sema][C++1z] Ensure structured binding's bindings in dependent foreach have non-null type

[Erik Pilkington via Phabricator via cfe-commits]

erik.pilkington created this revision.

A DecompositionDecls' bindings have a null type until the initializer is 
attached, if the initializer is dependent, then the bindings should be set to 
have dependent type. For non-foreach bindings, this is done in 
Sema::CheckCompleteDecompositionDeclaration(), this patch ensures that this is 
done to bindings in a foreach as well. Fixes PR32172.

Thanks for taking a look!
Erik


https://reviews.llvm.org/D34096

Files:
  lib/Sema/SemaStmt.cpp
  test/SemaCXX/cxx1z-decomposition.cpp


Index: test/SemaCXX/cxx1z-decomposition.cpp
===================================================================
--- test/SemaCXX/cxx1z-decomposition.cpp
+++ test/SemaCXX/cxx1z-decomposition.cpp
@@ -70,4 +70,10 @@
   return foobar_; // expected-error {{undeclared identifier 'foobar_'}}
 }
 
+// PR32172
+template <class T> void dependent_foreach(T t) {
+  for (auto [a,b,c] : t)
+    a,b,c;
+}
+
 // FIXME: by-value array copies
Index: lib/Sema/SemaStmt.cpp
===================================================================
--- lib/Sema/SemaStmt.cpp
+++ lib/Sema/SemaStmt.cpp
@@ -2206,8 +2206,12 @@
 
     // Deduce any 'auto's in the loop variable as 'DependentTy'. We'll fill
     // them in properly when we instantiate the loop.
-    if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check)
+    if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
+      if (auto *DD = dyn_cast<DecompositionDecl>(LoopVar))
+        for (auto *Binding : DD->bindings())
+          Binding->setType(Context.DependentTy);
       LoopVar->setType(SubstAutoType(LoopVar->getType(), Context.DependentTy));
+    }
   } else if (!BeginDeclStmt.get()) {
     SourceLocation RangeLoc = RangeVar->getLocation();
 



Index: test/SemaCXX/cxx1z-decomposition.cpp
===================================================================
--- test/SemaCXX/cxx1z-decomposition.cpp
+++ test/SemaCXX/cxx1z-decomposition.cpp
@@ -70,4 +70,10 @@
   return foobar_; // expected-error {{undeclared identifier 'foobar_'}}
 }
 
+// PR32172
+template <class T> void dependent_foreach(T t) {
+  for (auto [a,b,c] : t)
+    a,b,c;
+}
+
 // FIXME: by-value array copies
Index: lib/Sema/SemaStmt.cpp
===================================================================
--- lib/Sema/SemaStmt.cpp
+++ lib/Sema/SemaStmt.cpp
@@ -2206,8 +2206,12 @@
 
     // Deduce any 'auto's in the loop variable as 'DependentTy'. We'll fill
     // them in properly when we instantiate the loop.
-    if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check)
+    if (!LoopVar->isInvalidDecl() && Kind != BFRK_Check) {
+      if (auto *DD = dyn_cast<DecompositionDecl>(LoopVar))
+        for (auto *Binding : DD->bindings())
+          Binding->setType(Context.DependentTy);
       LoopVar->setType(SubstAutoType(LoopVar->getType(), Context.DependentTy));
+    }
   } else if (!BeginDeclStmt.get()) {
     SourceLocation RangeLoc = RangeVar->getLocation();
 

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