CPlusPlus: Do not ignore namespaces

... when comparing type names. For instance, this is relevant when
deciding whether to offer the "Apply signature changes" refactoring
action.
Add fallback code for function lookups, which was relying on the relaxed
semantics for parameter types.

Fixes: QTCREATORBUG-9856
Change-Id: I2001b77034ff15e96a23e3359d19654d0f43f60b
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/libs/3rdparty/cplusplus/Matcher.cpp

@@ -154,19 +154,7 @@ bool Matcher::match(const NamedType *type, const NamedType *otherType)
 {
     if (type == otherType)
         return true;
-
+    return Matcher::match(type->name(), otherType->name(), this);
-    const Name *name = type->name();
-    if (const QualifiedNameId *q = name->asQualifiedNameId())
-        name = q->name();
-
-    const Name *otherName = otherType->name();
-    if (const QualifiedNameId *q = otherName->asQualifiedNameId())
-        otherName = q->name();
-
-    if (! Matcher::match(name, otherName, this))
-        return false;
-
-    return true;
 }
 
 bool Matcher::match(const Function *type, const Function *otherType)

src/libs/3rdparty/cplusplus/Symbols.cpp

@@ -339,6 +339,28 @@ bool Function::isSignatureEqualTo(const Function *other, Matcher *matcher) const
     else if (! Matcher::match(unqualifiedName(), other->unqualifiedName(), matcher))
         return false;
 
+    class FallbackMatcher : public Matcher
+    {
+    public:
+        explicit FallbackMatcher(Matcher *baseMatcher) : m_baseMatcher(baseMatcher) {}
+
+    private:
+        bool match(const NamedType *type, const NamedType *otherType) override
+        {
+            if (type == otherType)
+                 return true;
+            const Name *name = type->name();
+            if (const QualifiedNameId *q = name->asQualifiedNameId())
+                name = q->name();
+            const Name *otherName = otherType->name();
+            if (const QualifiedNameId *q = otherName->asQualifiedNameId())
+                otherName = q->name();
+            return Matcher::match(name, otherName, m_baseMatcher);
+        }
+
+        Matcher * const m_baseMatcher;
+    } fallbackMatcher(matcher);
+
     const int argc = argumentCount();
     if (argc != other->argumentCount())
         return false;
@@ -359,6 +381,8 @@ bool Function::isSignatureEqualTo(const Function *other, Matcher *matcher) const
                 if (lType.match(rType))
                     continue;
             }
+            if (l->type().match(r->type(), &fallbackMatcher))
+                continue;
             return false;
         }
     }

src/plugins/cppeditor/cppfunctiondecldeflink.cpp

@@ -794,8 +794,9 @@ ChangeSet FunctionDeclDefLink::changes(const Snapshot &snapshot, int targetOffse
                     renamedTargetParameters[targetParam] = overview.prettyName(replacementName);
 
                 // need to change the type (and name)?
+                FullySpecifiedType replacementType = rewriteType(newParam->type(), &env, control);
                 if (!newParam->type().match(sourceParam->type())
-                        && !newParam->type().match(targetParam->type())) {
+                        && !replacementType.match(targetParam->type())) {
                     const int parameterTypeStart = targetFile->startOf(targetParamAst);
                     int parameterTypeEnd = 0;
                     if (targetParamAst->declarator)
@@ -805,7 +806,6 @@ ChangeSet FunctionDeclDefLink::changes(const Snapshot &snapshot, int targetOffse
                     else
                         parameterTypeEnd = targetFile->startOf(targetParamAst);
 
-                    FullySpecifiedType replacementType = rewriteType(newParam->type(), &env, control);
                     newTargetParam = targetFile->textOf(parameterStart, parameterTypeStart);
                     newTargetParam += overview.prettyType(replacementType, replacementName);
                     newTargetParam += targetFile->textOf(parameterTypeEnd, parameterEnd);