[Diagnostics] Refactor diagnoseAmbiguityWithFixes.

include/swift/AST/DiagnosticsSema.def

@@ -61,25 +61,13 @@ ERROR(ambiguous_member_overload_set,none,
 ERROR(ambiguous_reference_to_decl,none,
       "ambiguous reference to %0 %1", (DescriptiveDeclKind, DeclName))
 ERROR(no_overloads_match_exactly_in_call,none,
-      "no exact matches in call to %0 %1",
-      (DescriptiveDeclKind, DeclName))
-ERROR(no_overloads_match_exactly_in_call_no_labels,none,
-      "no exact matches in call to %0 %1",
-      (DescriptiveDeclKind, DeclBaseName))
-ERROR(no_overloads_match_exactly_in_call_special,none,
-      "no exact matches in call to %0",
-      (DescriptiveDeclKind))
-ERROR(no_overloads_match_exactly_in_assignment,none,
-      "no exact matches in assignment to %0",
-      (DeclBaseName))
+      "no exact matches in %select{reference|call}0 to %1 %select{%3|}2",
+      (bool, DescriptiveDeclKind, bool, DeclBaseName))
 
 NOTE(candidate_partial_match,none,
      "candidate has partially matching parameter list %0",
      (StringRef))
 
-ERROR(ambiguous_subscript,none,
-      "ambiguous subscript with base type %0 and index type %1",
-      (Type, Type))
 ERROR(could_not_find_value_subscript,none,
       "value of type %0 has no subscripts",
       (Type))
@@ -282,16 +270,6 @@ ERROR(no_candidates_match_result_type,none,
       "no '%0' candidates produce the expected contextual result type %1",
       (StringRef, Type))
 
-ERROR(candidates_no_match_result_type,none,
-      "'%0' produces %1, not the expected contextual result type %2",
-      (StringRef, Type, Type))
-
-
-
-ERROR(invalid_callee_result_type,none,
-      "cannot convert call result type %0 to expected type %1",
-      (Type, Type))
-
 
 ERROR(cannot_invoke_closure,none,
       "cannot invoke closure expression with an argument list of type '%0'",
@@ -407,6 +385,10 @@ ERROR(cannot_convert_argument_value_generic,none,
       "cannot convert value of type %0 (%1) to expected argument type %2 (%3)",
       (Type, StringRef, Type, StringRef))
 
+ERROR(conflicting_arguments_for_generic_parameter,none,
+      "conflicting arguments to generic parameter %0 (%1)",
+      (Type, StringRef))
+
 // @_nonEphemeral conversion diagnostics
 ERROR(cannot_pass_type_to_non_ephemeral,none,
       "cannot pass %0 to parameter; argument %1 must be a pointer that "

lib/Sema/CSDiag.cpp

@@ -1247,17 +1247,6 @@ void FailureDiagnosis::diagnoseAmbiguity(Expr *E) {
     return;
   }
 
-  // Diagnose ".foo" expressions that lack context specifically.
-  if (auto UME =
-        dyn_cast<UnresolvedMemberExpr>(E->getSemanticsProvidingExpr())) {
-    if (!CS.getContextualType(E)) {
-      diagnose(E->getLoc(), diag::unresolved_member_no_inference,UME->getName())
-        .highlight(SourceRange(UME->getDotLoc(),
-                               UME->getNameLoc().getSourceRange().End));
-      return;
-    }
-  }
-
   // Attempt to re-type-check the entire expression, allowing ambiguity, but
   // ignoring a contextual type.
   if (expr == E) {

lib/Sema/CSDiagnostics.cpp

@@ -5585,40 +5585,6 @@ bool ArgumentMismatchFailure::diagnoseArchetypeMismatch() const {
   if (!(paramDecl && argDecl))
     return false;
 
-  auto describeGenericType = [&](ValueDecl *genericParam,
-                                 bool includeName = false) -> std::string {
-    if (!genericParam)
-      return "";
-
-    Decl *parent = nullptr;
-    if (auto *AT = dyn_cast<AssociatedTypeDecl>(genericParam)) {
-      parent = AT->getProtocol();
-    } else {
-      auto *dc = genericParam->getDeclContext();
-      parent = dc->getInnermostDeclarationDeclContext();
-    }
-
-    if (!parent)
-      return "";
-
-    llvm::SmallString<64> result;
-    llvm::raw_svector_ostream OS(result);
-
-    OS << Decl::getDescriptiveKindName(genericParam->getDescriptiveKind());
-
-    if (includeName && genericParam->hasName())
-      OS << " '" << genericParam->getBaseName() << "'";
-
-    OS << " of ";
-    OS << Decl::getDescriptiveKindName(parent->getDescriptiveKind());
-    if (auto *decl = dyn_cast<ValueDecl>(parent)) {
-      if (decl->hasName())
-        OS << " '" << decl->getFullName() << "'";
-    }
-
-    return OS.str();
-  };
-
   emitDiagnostic(
       getAnchor()->getLoc(), diag::cannot_convert_argument_value_generic, argTy,
       describeGenericType(argDecl), paramTy, describeGenericType(paramDecl));

lib/Sema/CSFix.cpp

@@ -479,6 +479,24 @@ bool DefineMemberBasedOnUse::diagnose(bool asNote) const {
   return AlreadyDiagnosed || failure.diagnose(asNote);
 }
 
+bool
+DefineMemberBasedOnUse::diagnoseForAmbiguity(ArrayRef<Solution> solutions) const {
+  Type concreteBaseType;
+  for (const auto &solution: solutions) {
+    auto baseType = solution.simplifyType(BaseType);
+    if (!concreteBaseType)
+      concreteBaseType = baseType;
+
+    if (concreteBaseType->getCanonicalType() != baseType->getCanonicalType()) {
+      getConstraintSystem().getASTContext().Diags.diagnose(getAnchor()->getLoc(),
+          diag::unresolved_member_no_inference, Name);
+      return true;
+    }
+  }
+
+  return diagnose();
+}
+
 DefineMemberBasedOnUse *
 DefineMemberBasedOnUse::create(ConstraintSystem &cs, Type baseType,
                                DeclNameRef member, bool alreadyDiagnosed,
@@ -1088,6 +1106,12 @@ UseValueTypeOfRawRepresentative::attempt(ConstraintSystem &cs, Type argType,
   return nullptr;
 }
 
+unsigned AllowArgumentMismatch::getParamIdx() const {
+  const auto *locator = getLocator();
+  auto elt = locator->castLastElementTo<LocatorPathElt::ApplyArgToParam>();
+  return elt.getParamIdx();
+}
+
 bool AllowArgumentMismatch::diagnose(bool asNote) const {
   auto &cs = getConstraintSystem();
   ArgumentMismatchFailure failure(cs, getFromType(), getToType(),

lib/Sema/CSFix.h

@@ -289,6 +289,8 @@ class ConstraintFix {
   /// Diagnose a failure associated with this fix.
   virtual bool diagnose(bool asNote = false) const = 0;
 
+  virtual bool diagnoseForAmbiguity(ArrayRef<Solution> solutions) const { return false; }
+
   void print(llvm::raw_ostream &Out) const;
 
   SWIFT_DEBUG_DUMP;
@@ -843,6 +845,8 @@ class DefineMemberBasedOnUse final : public ConstraintFix {
 
   bool diagnose(bool asNote = false) const override;
 
+  bool diagnoseForAmbiguity(ArrayRef<Solution> solutions) const override;
+
   static DefineMemberBasedOnUse *create(ConstraintSystem &cs, Type baseType,
                                         DeclNameRef member, bool alreadyDiagnosed,
                                         ConstraintLocator *locator);
@@ -1109,6 +1113,10 @@ class AddMissingArguments final
 
   bool diagnose(bool asNote = false) const override;
 
+  bool diagnoseForAmbiguity(ArrayRef<Solution> solutions) const override {
+    return diagnose();
+  }
+
   static AddMissingArguments *create(ConstraintSystem &cs,
                                      llvm::ArrayRef<Param> synthesizedArgs,
                                      ConstraintLocator *locator);
@@ -1149,6 +1157,10 @@ class RemoveExtraneousArguments final
 
   bool diagnose(bool asNote = false) const override;
 
+  bool diagnoseForAmbiguity(ArrayRef<Solution> solutions) const override {
+    return diagnose();
+  }
+
   /// FIXME(diagnostics): Once `resolveDeclRefExpr` is gone this
   /// logic would be obsolete.
   ///
@@ -1349,6 +1361,10 @@ class DefaultGenericArgument final : public ConstraintFix {
 
   bool diagnose(bool asNote = false) const override;
 
+  bool diagnoseForAmbiguity(ArrayRef<Solution> solutions) const override {
+    return diagnose();
+  }
+
   static DefaultGenericArgument *create(ConstraintSystem &cs,
                                         GenericTypeParamType *param,
                                         ConstraintLocator *locator);
@@ -1420,6 +1436,10 @@ class IgnoreContextualType : public ContextualMismatch {
 
   bool diagnose(bool asNote = false) const override;
 
+  bool diagnoseForAmbiguity(ArrayRef<Solution> solutions) const override {
+    return diagnose();
+  }
+
   static IgnoreContextualType *create(ConstraintSystem &cs, Type resultTy,
                                       Type specifiedTy,
                                       ConstraintLocator *locator);
@@ -1479,11 +1499,17 @@ class AllowArgumentMismatch : public ContextualMismatch {
     return "allow argument to parameter type conversion mismatch";
   }
 
+  unsigned getParamIdx() const;
+
   bool diagnose(bool asNote = false) const override;
 
   static AllowArgumentMismatch *create(ConstraintSystem &cs, Type argType,
                                        Type paramType,
                                        ConstraintLocator *locator);
+
+  static bool classof(const ConstraintFix *fix) {
+    return fix->getKind() == FixKind::AllowArgumentTypeMismatch;
+  }
 };
 
 class ExpandArrayIntoVarargs final : public AllowArgumentMismatch {