[PATCH] D51880: [ASTMatchers] add two matchers for dependent expressions

[Jonas Toth via Phabricator via cfe-commits]

JonasToth created this revision.
JonasToth added reviewers: aaron.ballman, alexfh, klimek.
Herald added a subscriber: cfe-commits.

The new matchers can be used to check if an expression is type- or value-dependent
in a templated context.
These matchers are used in a clang-tidy check and generally useful as the
problem of unresolved templates occurs more often in clang-tidy and they
provide an easy way to check for this issue.


Repository:
  rC Clang

https://reviews.llvm.org/D51880

Files:
  docs/LibASTMatchersReference.html
  include/clang/ASTMatchers/ASTMatchers.h


Index: include/clang/ASTMatchers/ASTMatchers.h
===================================================================
--- include/clang/ASTMatchers/ASTMatchers.h
+++ include/clang/ASTMatchers/ASTMatchers.h
@@ -774,6 +774,29 @@
   return InnerMatcher.matches(*Node.IgnoreParenCasts(), Finder, Builder);
 }
 
+/// Matches expressions that are type-dependant because the template type
+/// is not yet instantiated.
+///
+/// For example, the expressions "x" and "x + y" are type-dependent in
+/// the following code, but "y" is not type-dependent:
+/// \code
+///   template<typename T>
+///   void add(T x, int y) {
+///     x + y;
+///   }
+/// \endcode
+AST_MATCHER(Expr, isTypeDependent) { return Node.isTypeDependent(); }
+
+/// Matches expression that are value-dependant because they contain a
+/// non-type template parameter.
+///
+/// For example, the array bound of "Chars" in the following example is
+/// value-dependent.
+/// \code
+///   template<int Size, char (&Chars)[Size]> struct meta_string;
+/// \endcode
+AST_MATCHER(Expr, isValueDependent) { return Node.isValueDependent(); }
+
 /// Matches expressions that match InnerMatcher after implicit casts and
 /// parentheses are stripped off.
 ///
Index: docs/LibASTMatchersReference.html
===================================================================
--- docs/LibASTMatchersReference.html
+++ docs/LibASTMatchersReference.html
@@ -2758,6 +2758,29 @@
 </pre></td></tr>
 
 
+<tr><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>></td><td class="name" onclick="toggle('isTypeDependent0')"><a name="isTypeDependent0Anchor">isTypeDependent</a></td><td></td></tr>
+<tr><td colspan="4" class="doc" id="isTypeDependent0"><pre>Matches expressions that are type-dependant because the template type
+is not yet instantiated.
+
+For example, the expressions "x" and "x + y" are type-dependent in
+the following code, but "y" is not type-dependent:
+  template<typename T>
+  void add(T x, int y) {
+    x + y;
+  }
+</pre></td></tr>
+
+
+<tr><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1Expr.html">Expr</a>></td><td class="name" onclick="toggle('isValueDependent0')"><a name="isValueDependent0Anchor">isValueDependent</a></td><td></td></tr>
+<tr><td colspan="4" class="doc" id="isValueDependent0"><pre>Matches expression that are value-dependant because they contain a
+non-type template parameter.
+
+For example, the array bound of "Chars" in the following example is
+value-dependent.
+  template<int Size, char (&Chars)[Size]> struct meta_string;
+</pre></td></tr>
+
+
 <tr><td>Matcher<<a href="http://clang.llvm.org/doxygen/classclang_1_1FieldDecl.html">FieldDecl</a>></td><td class="name" onclick="toggle('hasBitWidth0')"><a name="hasBitWidth0Anchor">hasBitWidth</a></td><td>unsigned Width</td></tr>
 <tr><td colspan="4" class="doc" id="hasBitWidth0"><pre>Matches non-static data members that are bit-fields of the specified
 bit width.


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