[SemaCXX] Param diagnostic matches overload logic

Summary:
Given the following test program:

```
class C {
public:
int A(int a, int& b);
};

int C::A(const int a, int b) {
return a * b;
}
```

[SemaCXX] Param diagnostic matches overload logic

Summary:
Given the following test program:

```
class C {
public:
int A(int a, int& b);
};

int C::A(const int a, int b) {
return a * b;
}
```

Clang would produce an error message that correctly diagnosed the
redeclaration of `C::A` to not match the original declaration (the
parameters to the two declarations do not match -- the original takes an
`int &` as its 2nd parameter, but the redeclaration takes an `int`). However,
it also produced a note diagnostic that inaccurately pointed to the
first parameter, claiming that `const int` in the redeclaration did not
match the unqualified `int` in the original. The diagnostic is
misleading because it has nothing to do with why the program does not
compile.

The logic for checking for a function overload, in
`Sema::FunctionParamTypesAreEqual`, discards cv-qualifiers before
checking whether the types are equal. Do the same when producing the
overload diagnostic.

Reviewers: rsmith

Reviewed By: rsmith

Subscribers: cpplearner, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D57032

llvm-svn: 352831

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Functions declared in a scope should not hide previous declaration in earlier scopes

This code should be an error:

void foo(int);
void f3() {
int foo(float);
{
float foo(int); // expec

Functions declared in a scope should not hide previous declaration in earlier scopes

This code should be an error:

void foo(int);
void f3() {
int foo(float);
{
float foo(int); // expected-error {{functions that differ only in their return type cannot be overloaded}}
}
}

the foo(float) function declared at function scope should not hide the float(int)
while trying to redeclare functions.

Differential Revision: http://reviews.llvm.org/D19763

llvm-svn: 272961

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Switch the semantic DeclContext for a block-scope declaration of a function or
variable from being the function to being the enclosing namespace scope (in
C++) or the TU (in C). This allows us to fix

Switch the semantic DeclContext for a block-scope declaration of a function or
variable from being the function to being the enclosing namespace scope (in
C++) or the TU (in C). This allows us to fix a selection of related issues
where we would build incorrect redeclaration chains for such declarations, and
fail to notice type mismatches.

Such declarations are put into a new IdentifierNamespace, IDNS_LocalExtern,
which is only found when searching scopes, and not found when searching
DeclContexts. Such a declaration is only made visible in its DeclContext if
there are no non-LocalExtern declarations.

llvm-svn: 191064

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Fix implementation of C11 6.2.7/4 and C++11 [dcl.array]p3:

When a local extern declaration redeclares some other entity, the type of that
entity is merged with the prior type if the prior declaratio

Fix implementation of C11 6.2.7/4 and C++11 [dcl.array]p3:

When a local extern declaration redeclares some other entity, the type of that
entity is merged with the prior type if the prior declaration is visible (in C)
or is declared in the same scope (in C++).

- Make LookupRedeclarationWithLinkage actually work in C++, use it in the right
set of cases, and make it track whether it found a shadowed declaration.
- Track whether we found a declaration in the same scope (for C++) including
across serialization and template instantiation.

llvm-svn: 188307

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Move the extern "C" sema tests to a new file.

llvm-svn: 176888

We already reported an error for

extern "C" {
void test5_f() {
extern int test5_b;
}
}
static float test5_b;

This patch makes us report one for

extern "C" {
void test6_f() {
extern i

We already reported an error for

extern "C" {
void test5_f() {
extern int test5_b;
}
}
static float test5_b;

This patch makes us report one for

extern "C" {
void test6_f() {
extern int test6_b;
}
}
extern "C" {
static float test6_b;
}

Not because we think the declaration would be extern C, but because of the rule:

An entity with C language linkage shall not be declared with the same name as an entity in global scope...

We were just not looking past the extern "C" to see if the decl was in global
scope.

llvm-svn: 176875

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Error if an extern C declaration matches a previous hidden extern C declaration.

Without this patch we produce an error for

extern "C" {
void f() {
extern int b;
}
}
extern "C" {
extern f

Error if an extern C declaration matches a previous hidden extern C declaration.

Without this patch we produce an error for

extern "C" {
void f() {
extern int b;
}
}
extern "C" {
extern float b;
}

but not for

extern "C" {
void f() {
extern int b;
}
}
extern "C" {
float b;
}

llvm-svn: 176867

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Reject incompatible redeclarations of extern C symbols.

Before we were only checking if the new declaration itself was marked extern
C. Fixes prpr14766.

llvm-svn: 172243

Ignore corrections to functions with bodies when deciding which
correction to use for an invalid function redeclaration.

llvm-svn: 158177

Remove more redundant lookups. Add a new "all_lookups_iterator" which provides
a view over the contents of a DeclContext without exposing the implementation
details of the StoredDeclsMap. Use this in

Remove more redundant lookups. Add a new "all_lookups_iterator" which provides
a view over the contents of a DeclContext without exposing the implementation
details of the StoredDeclsMap. Use this in LookupVisibleDecls to find the
visible declarations. Fixes PR12339!

llvm-svn: 153970

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Only accept a typo correction if it doesn't trigger additional errors

llvm-svn: 141609

Give nicer note when a member redeclaration has or lacks 'const'

llvm-svn: 141555

Plug an abstraction leak and fix a crasher in DiagnoseInvalidRedeclaration

llvm-svn: 139718

Fix an incorrect note.

For the test case added to function-redecl.cpp, we were previously complaining
about a mismatch in the parameter types, since the definition used the
typedef'd type.

llvm-svn

Fix an incorrect note.

For the test case added to function-redecl.cpp, we were previously complaining
about a mismatch in the parameter types, since the definition used the
typedef'd type.

llvm-svn: 138318

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Don't accept a typo correction if the corrected identifier is the same as the
uncorrected identifier. Fixes a problem pointed out by Eli.

llvm-svn: 137987

Rework DiagnoseInvalidRedeclaration to add the ability to correct typos when
diagnosing invalid function redeclarations.

llvm-svn: 137966

Update tests to use %clang_cc1 instead of 'clang-cc' or 'clang -cc1'.
- This is designed to make it obvious that %clang_cc1 is a "test variable"
which is substituted. It is '%clang_cc1' instead o

Update tests to use %clang_cc1 instead of 'clang-cc' or 'clang -cc1'.
- This is designed to make it obvious that %clang_cc1 is a "test variable"
which is substituted. It is '%clang_cc1' instead of '%clang -cc1' because it
can be useful to redefine what gets run as 'clang -cc1' (for example, to set
a default target).

llvm-svn: 91446

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Rename clang to clang-cc.

Tests and drivers updated, still need to shuffle dirs.

llvm-svn: 67602

Improve merging of function declarations. Specifically:

- When we are declaring a function in local scope, we can merge with
a visible declaration from an outer scope if that declaration
r

Improve merging of function declarations. Specifically:

- When we are declaring a function in local scope, we can merge with
a visible declaration from an outer scope if that declaration
refers to an entity with linkage. This behavior now works in C++
and properly ignores entities without linkage.
- Diagnose the use of "static" on a function declaration in local
scope.
- Diagnose the declaration of a static function after a non-static
declaration of the same function.
- Propagate the storage specifier to a function declaration from a
prior declaration (PR3425)
- Don't name-mangle "main"

llvm-svn: 65360

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