Suggest fix-it ':' when '=' used in for-range-declaration

Fix for PR19176. Clang will suggest a fix-it hint for cases like:
  int arr[] = {1, 2, 3, 4};
  for (auto i = arr)
              ^
              :

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@208299 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/DiagnosticParseKinds.td b/include/clang/Basic/DiagnosticParseKinds.td
index 335b6abf1346d5cb12f68de23f7009f145a4ffd5..70e16ceca1c5c7b63ca4a74da936134239e41c1f 100644 (file)
--- a/include/clang/Basic/DiagnosticParseKinds.td
+++ b/include/clang/Basic/DiagnosticParseKinds.td
@@ -204,6 +204,8 @@ def err_expected_semi_after_attribute_list : Error<
 def err_expected_semi_after_static_assert : Error<
   "expected ';' after static_assert">;
 def err_expected_semi_for : Error<"expected ';' in 'for' statement specifier">;
+def err_single_decl_assign_in_for_range : Error<
+  "range based for statement requires ':' after range declaration">;
 def warn_missing_selector_name : Warning<
   "%0 used as the name of the previous parameter rather than as part "
   "of the selector">,

diff --git a/include/clang/Parse/Parser.h b/include/clang/Parse/Parser.h
index 0b15eb68417acbef9f225796ca83c484f8a191e1..79c65c6db47c3aa539a2c0186be18a720379ef6e 100644 (file)
--- a/include/clang/Parse/Parser.h
+++ b/include/clang/Parse/Parser.h
@@ -1727,8 +1727,10 @@ private:
   Decl *ParseDeclarationAfterDeclarator(Declarator &D,
                const ParsedTemplateInfo &TemplateInfo = ParsedTemplateInfo());
   bool ParseAsmAttributesAfterDeclarator(Declarator &D);
-  Decl *ParseDeclarationAfterDeclaratorAndAttributes(Declarator &D,
-               const ParsedTemplateInfo &TemplateInfo = ParsedTemplateInfo());
+  Decl *ParseDeclarationAfterDeclaratorAndAttributes(
+      Declarator &D,
+      const ParsedTemplateInfo &TemplateInfo = ParsedTemplateInfo(),
+      ForRangeInit *FRI = nullptr);
   Decl *ParseFunctionStatementBody(Decl *Decl, ParseScope &BodyScope);
   Decl *ParseFunctionTryBlock(Decl *Decl, ParseScope &BodyScope);
 

diff --git a/lib/Parse/ParseDecl.cpp b/lib/Parse/ParseDecl.cpp
index 42369bfbc928a5549c9018e5b971d0e0e90bb40e..3c1c378dbff367a78396d0a170bf5c955a205ce9 100644 (file)
--- a/lib/Parse/ParseDecl.cpp
+++ b/lib/Parse/ParseDecl.cpp
@@ -1620,7 +1620,8 @@ Parser::DeclGroupPtrTy Parser::ParseDeclGroup(ParsingDeclSpec &DS,
   }
 
   SmallVector<Decl *, 8> DeclsInGroup;
-  Decl *FirstDecl = ParseDeclarationAfterDeclaratorAndAttributes(D);
+  Decl *FirstDecl = ParseDeclarationAfterDeclaratorAndAttributes(
+      D, ParsedTemplateInfo(), FRI);
   if (LateParsedAttrs.size() > 0)
     ParseLexedAttributeList(LateParsedAttrs, FirstDecl, true, false);
   D.complete(FirstDecl);
@@ -1726,16 +1727,16 @@ bool Parser::ParseAsmAttributesAfterDeclarator(Declarator &D) {
 /// According to the standard grammar, =default and =delete are function
 /// definitions, but that definitely doesn't fit with the parser here.
 ///
-Decl *Parser::ParseDeclarationAfterDeclarator(Declarator &D,
-                                     const ParsedTemplateInfo &TemplateInfo) {
+Decl *Parser::ParseDeclarationAfterDeclarator(
+    Declarator &D, const ParsedTemplateInfo &TemplateInfo) {
   if (ParseAsmAttributesAfterDeclarator(D))
     return 0;
 
   return ParseDeclarationAfterDeclaratorAndAttributes(D, TemplateInfo);
 }
 
-Decl *Parser::ParseDeclarationAfterDeclaratorAndAttributes(Declarator &D,
-                                     const ParsedTemplateInfo &TemplateInfo) {
+Decl *Parser::ParseDeclarationAfterDeclaratorAndAttributes(
+    Declarator &D, const ParsedTemplateInfo &TemplateInfo, ForRangeInit *FRI) {
   // Inform the current actions module that we just parsed this declarator.
   Decl *ThisDecl = 0;
   switch (TemplateInfo.Kind) {
@@ -1800,7 +1801,7 @@ Decl *Parser::ParseDeclarationAfterDeclaratorAndAttributes(Declarator &D,
   // Parse declarator '=' initializer.
   // If a '==' or '+=' is found, suggest a fixit to '='.
   if (isTokenEqualOrEqualTypo()) {
-    ConsumeToken();
+    SourceLocation EqualLoc = ConsumeToken();
 
     if (Tok.is(tok::kw_delete)) {
       if (D.isFunctionDeclarator())
@@ -1829,13 +1830,29 @@ Decl *Parser::ParseDeclarationAfterDeclaratorAndAttributes(Declarator &D,
 
       ExprResult Init(ParseInitializer());
 
+      // If this is the only decl in (possibly) range based for statement,
+      // our best guess is that the user meant ':' instead of '='.
+      if (Tok.is(tok::r_paren) && FRI && D.isFirstDeclarator()) {
+        Diag(EqualLoc, diag::err_single_decl_assign_in_for_range)
+            << FixItHint::CreateReplacement(EqualLoc, ":");
+        // We are trying to stop parser from looking for ';' in this for
+        // statement, therefore preventing spurious errors to be issued.
+        FRI->ColonLoc = EqualLoc;
+        Init = ExprError();
+        FRI->RangeExpr = Init;
+      }
+
       if (getLangOpts().CPlusPlus && D.getCXXScopeSpec().isSet()) {
         Actions.ActOnCXXExitDeclInitializer(getCurScope(), ThisDecl);
         ExitScope();
       }
 
       if (Init.isInvalid()) {
-        SkipUntil(tok::comma, StopAtSemi | StopBeforeMatch);
+        SmallVector<tok::TokenKind, 2> StopTokens;
+        StopTokens.push_back(tok::comma);
+        if (D.getContext() == Declarator::ForContext)
+          StopTokens.push_back(tok::r_paren);
+        SkipUntil(StopTokens, StopAtSemi | StopBeforeMatch);
         Actions.ActOnInitializerError(ThisDecl);
       } else
         Actions.AddInitializerToDecl(ThisDecl, Init.take(),

diff --git a/lib/Parse/ParseStmt.cpp b/lib/Parse/ParseStmt.cpp
index eafe334891965862a7b4cf646d2db345fb5894fd..a187b2ce3e417fe4060efd9784829b9f48e856c3 100644 (file)
--- a/lib/Parse/ParseStmt.cpp
+++ b/lib/Parse/ParseStmt.cpp
@@ -1479,12 +1479,10 @@ StmtResult Parser::ParseForStatement(SourceLocation *TrailingElseLoc) {
 
     SourceLocation DeclStart = Tok.getLocation(), DeclEnd;
     StmtVector Stmts;
-    DeclGroupPtrTy DG = ParseSimpleDeclaration(Stmts, Declarator::ForContext,
-                                               DeclEnd, attrs, false,
-                                               MightBeForRangeStmt ?
-                                                 &ForRangeInit : 0);
+    DeclGroupPtrTy DG = ParseSimpleDeclaration(
+        Stmts, Declarator::ForContext, DeclEnd, attrs, false,
+        MightBeForRangeStmt ? &ForRangeInit : nullptr);
     FirstPart = Actions.ActOnDeclStmt(DG, DeclStart, Tok.getLocation());
-
     if (ForRangeInit.ParsedForRangeDecl()) {
       Diag(ForRangeInit.ColonLoc, getLangOpts().CPlusPlus11 ?
            diag::warn_cxx98_compat_for_range : diag::ext_for_range);

diff --git a/test/Parser/cxx0x-for-range.cpp b/test/Parser/cxx0x-for-range.cpp
index f920ef9085b161adac8e210bc63ace86826a8b03..f75b67c486f5a428c547078583dcadd23fa4cc44 100644 (file)
--- a/test/Parser/cxx0x-for-range.cpp
+++ b/test/Parser/cxx0x-for-range.cpp
@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 %s
+// RUN: not %clang_cc1 -fsyntax-only -fdiagnostics-parseable-fixits -std=c++11 %s 2>&1 | FileCheck %s
 
 template<typename T, typename U>
 struct pair {};
@@ -28,3 +28,35 @@ int foo(map<char*,int> &m) {
 
   return n;
 }
+
+namespace PR19176 {
+struct Vector {
+  struct iterator {
+    int &operator*();
+    iterator &operator++();
+    iterator &operator++(int);
+    bool operator==(const iterator &) const;
+  };
+  iterator begin();
+  iterator end();
+};
+
+void f() {
+  Vector v;
+  int a[] = {1, 2, 3, 4};
+  for (auto foo   =     a) // expected-error {{range based for statement requires ':' after range declaration}}
+    // CHECK: fix-it:"{{.*}}":{[[@LINE-1]]:19-[[@LINE-1]]:20}:":"
+    (void)foo;
+  for (auto i
+      =
+      v) // expected-error@-1 {{range based for statement requires ':' after range declaration}}
+    // CHECK: fix-it:"{{.*}}":{[[@LINE-2]]:7-[[@LINE-2]]:8}:":"
+    (void)i;
+#define FORRANGE(v, a) for (DECLVARWITHINIT(v) a)  // expected-note {{expanded from macro}}
+#define DECLAUTOVAR(v) auto v
+#define DECLVARWITHINIT(v) DECLAUTOVAR(v) =  // expected-note {{expanded from macro}}
+  FORRANGE(i, a) {  // expected-error {{range based for statement requires ':' after range declaration}}
+
+  }
+}
+}