Improve handling of initializers in @available(renamed:).

If we know the renamed thing is being called, we can just use
"Foo(...)" in the resulting expression (rather than "Foo.init(...)").

Author: jrose-apple

lib/Sema/MiscDiagnostics.cpp

@@ -1115,6 +1115,12 @@ void swift::fixItAvailableAttrRename(TypeChecker &TC,
 
     // Continue on to diagnose any argument label renames.
 
+  } else if (parsed.BaseName == TC.Context.Id_init.str() &&
+             parsed.isMember() && CE) {
+    // For initializers, replace with a "call" of the context type...but only
+    // if we know we're doing a call (rather than a first-class reference).
+    diag.fixItReplace(referenceRange, parsed.ContextName);
+
   } else {
     // Just replace the base name.
     SmallString<64> baseReplace;

test/attr/attr_availability.swift

@@ -296,6 +296,9 @@ func unavailableMultiUnnamedSame(_ a: Int, _ b: Int) {} // expected-note {{here}
 @available(*, unavailable, renamed: "shinyLabeledArguments(_:_:)")
 func unavailableMultiNewlyUnnamed(a: Int, b: Int) {} // expected-note {{here}}
 
+@available(*, unavailable, renamed: "Int.init(other:)")
+func unavailableInit(a: Int) {} // expected-note 2 {{here}}
+
 
 func testArgNames() {
   unavailableArgNames(a: 0) // expected-error {{'unavailableArgNames(a:)' has been renamed to 'shinyLabeledArguments(example:)'}} {{3-22=shinyLabeledArguments}} {{23-24=example}}
@@ -317,6 +320,10 @@ func testArgNames() {
   unavailableMultiUnnamed(0, 1) // expected-error {{'unavailableMultiUnnamed' has been renamed to 'shinyLabeledArguments(example:another:)'}} {{3-26=shinyLabeledArguments}} {{27-27=example: }} {{30-30=another: }}
   unavailableMultiUnnamedSame(0, 1) // expected-error {{'unavailableMultiUnnamedSame' has been renamed to 'shinyLabeledArguments(_:_:)'}} {{3-30=shinyLabeledArguments}}
   unavailableMultiNewlyUnnamed(a: 0, b: 1) // expected-error {{'unavailableMultiNewlyUnnamed(a:b:)' has been renamed to 'shinyLabeledArguments(_:_:)'}} {{3-31=shinyLabeledArguments}} {{32-35=}} {{38-41=}}
+
+  unavailableInit(a: 0) // expected-error {{'unavailableInit(a:)' has been replaced by 'Int.init(other:)'}} {{3-18=Int}} {{19-20=other}}
+  let fn = unavailableInit // expected-error {{'unavailableInit(a:)' has been replaced by 'Int.init(other:)'}} {{12-27=Int.init}}
+  fn(a: 1)
 }
 
 @available(*, unavailable, renamed: "shinyLabeledArguments()")