[Diagnostics] Introdduce multiple extraneous arguments diagnostic

Author: xedin

include/swift/AST/DiagnosticsSema.def

@@ -1122,6 +1122,8 @@ ERROR(extra_argument_named,none,
       "extra argument %0 in call", (Identifier))
 ERROR(extra_argument_positional,none,
       "extra argument in call", ())
+ERROR(extra_arguments_in_call,none,
+      "extra arguments at positions %0 in call", (StringRef))
 ERROR(extra_argument_to_nullary_call,none,
       "argument passed to call that takes no arguments", ())
 ERROR(extra_trailing_closure_in_call,none,

lib/Sema/CSDiagnostics.cpp

@@ -4285,7 +4285,28 @@ bool ExtraneousArgumentsFailure::diagnoseAsError() {
     }
   }
 
-  return false;
+  if (ExtraArgs.size() < 2)
+    return false;
+
+  llvm::SmallString<64> positions;
+  llvm::raw_svector_ostream OS(positions);
+
+  interleave(
+      ExtraArgs,
+      [&](const std::pair<unsigned, AnyFunctionType::Param> &arg) {
+        OS << "#" << (arg.first + 1);
+      },
+      [&] { OS << ", "; });
+
+  emitDiagnostic(anchor->getLoc(), diag::extra_arguments_in_call, OS.str());
+
+  if (auto overload = getChoiceFor(getLocator())) {
+    if (auto *decl = overload->choice.getDeclOrNull()) {
+      emitDiagnostic(decl, diag::decl_declared_here, decl->getFullName());
+    }
+  }
+
+  return true;
 }
 
 bool ExtraneousArgumentsFailure::diagnoseAsNote() {

test/Constraints/keyword_arguments.swift

@@ -255,22 +255,20 @@ missingargs2(x: 1, y: 2) // expected-error{{missing argument for parameter #3 in
 // -------------------------------------------
 // Extra arguments
 // -------------------------------------------
-// FIXME: Diagnostics could be improved with all extra arguments and
-// note pointing to the declaration being called.
-func extraargs1(x: Int) {}
+func extraargs1(x: Int) {} // expected-note {{'extraargs1(x:)' declared here}}
 
 extraargs1(x: 1, y: 2) // expected-error{{extra argument 'y' in call}}
-extraargs1(x: 1, 2, 3) // expected-error{{extra argument in call}}
+extraargs1(x: 1, 2, 3) // expected-error{{extra arguments at positions #2, #3 in call}}
 
 // -------------------------------------------
 // Argument name mismatch
 // -------------------------------------------
 
-func mismatch1(thisFoo: Int = 0, bar: Int = 0, wibble: Int = 0) { }
+func mismatch1(thisFoo: Int = 0, bar: Int = 0, wibble: Int = 0) { } // expected-note {{'mismatch1(thisFoo:bar:wibble:)' declared here}}
 
 mismatch1(foo: 5) // expected-error {{extra argument 'foo' in call}}
 mismatch1(baz: 1, wobble: 2) // expected-error{{incorrect argument labels in call (have 'baz:wobble:', expected 'bar:wibble:')}} {{11-14=bar}} {{19-25=wibble}}
-mismatch1(food: 1, zap: 2) // expected-error{{extra argument 'food' in call}}
+mismatch1(food: 1, zap: 2) // expected-error{{extra arguments at positions #1, #2 in call}}
 
 // -------------------------------------------
 // Subscript keyword arguments