Improve diagnostics when we fail to convert from a source type to a

destination type for initialization, assignment, parameter-passing,
etc. The main issue fixed here is that we used rather confusing
wording for diagnostics such as

t.c:2:9: warning: initializing 'char const [2]' discards qualifiers,
      expected 'char *' [-pedantic]
  char *name = __func__;
        ^      ~~~~~~~~

We're not initializing a 'char const [2]', we're initializing a 'char
*' with an expression of type 'char const [2]'. Similar problems
existed for other diagnostics in this area, so I've normalized them all
with more precise descriptive text to say what we're
initializing/converting/assigning/etc. from and to. The warning for
the code above is now:

t.c:2:9: warning: initializing 'char *' from an expression of type
      'char const [2]' discards qualifiers [-pedantic]
  char *name = __func__;
        ^      ~~~~~~~~

Fixes <rdar://problem/7447179>.

llvm-svn: 100832

1 files changed, 21 insertions, 1 deletions

diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index da0c0a04992..654b2204995 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -7201,7 +7201,27 @@ bool Sema::DiagnoseAssignmentResult(AssignConvertType ConvTy,
     break;
   }
 
-  Diag(Loc, DiagKind) << DstType << SrcType << Action
+  QualType FirstType, SecondType;
+  switch (Action) {
+  case AA_Assigning:
+  case AA_Initializing:
+    // The destination type comes first.
+    FirstType = DstType;
+    SecondType = SrcType;
+    break;
+      
+  case AA_Returning:
+  case AA_Passing:
+  case AA_Converting:
+  case AA_Sending:
+  case AA_Casting:
+    // The source type comes first.
+    FirstType = SrcType;
+    SecondType = DstType;
+    break;
+  }
+  
+  Diag(Loc, DiagKind) << FirstType << SecondType << Action
     << SrcExpr->getSourceRange() << Hint;
   return isInvalid;
 }