[CS] Look at the fn's rvalue type in getCalleeLocator

This makes sure we correctly resolve to the initialiser decl rather than
an lvalue local variable of a metatype in the included test case.

Author: hamishknight

lib/Sema/ConstraintSystem.cpp

@@ -425,7 +425,8 @@ ConstraintLocator *ConstraintSystem::getCalleeLocator(Expr *expr) {
     // For an apply of a metatype, we have a short-form constructor. Unlike
     // other locators to callees, these are anchored on the apply expression
     // rather than the function expr.
-    if (simplifyType(getType(fnExpr))->is<AnyMetatypeType>()) {
+    auto fnTy = getFixedTypeRecursive(getType(fnExpr), /*wantRValue*/ true);
+    if (fnTy->is<AnyMetatypeType>()) {
       auto *fnLocator =
           getConstraintLocator(applyExpr, ConstraintLocator::ApplyFunction);
       return getConstraintLocator(fnLocator,

test/Constraints/generics.swift

@@ -714,7 +714,7 @@ protocol Q {
 }
 
 struct SR10694 {
-  init<T : P>(_ x: T) {} // expected-note 2{{where 'T' = 'T'}}
+  init<T : P>(_ x: T) {} // expected-note 3{{where 'T' = 'T'}}
   func bar<T>(_ x: T, _ s: SR10694, _ q: Q) {
     SR10694.self(x) // expected-error {{initializer 'init(_:)' requires that 'T' conform to 'P'}}
 
@@ -726,6 +726,10 @@ struct SR10694 {
 
     type(of: q)(x)  // expected-error {{initializer 'init(_:)' requires that 'T' conform to 'P'}}
     // expected-error@-1 {{initializing from a metatype value must reference 'init' explicitly}}
+
+    var srTy = SR10694.self
+    srTy(x) // expected-error {{initializer 'init(_:)' requires that 'T' conform to 'P'}}
+    // expected-error@-1 {{initializing from a metatype value must reference 'init' explicitly}}
   }
 }