[CSFix] Generalize a fix for unresolved pattern decl

The fix should support both named (i.e. `test(a)` and "any" patterns
i.e. `test(_)`.

Author: xedin

include/swift/Sema/CSFix.h

@@ -298,9 +298,9 @@ enum class FixKind : uint8_t {
   /// Ignore `ErrorExpr` or `ErrorType` during pre-check.
   IgnoreInvalidASTNode,
 
-  /// Ignore a named pattern whose type we couldn't infer. This issue should
-  /// already have been diagnosed elsewhere.
-  IgnoreInvalidNamedPattern,
+  /// Ignore a named or `_` pattern whose type we couldn't infer.
+  /// This issue should already have been diagnosed elsewhere.
+  IgnoreUnresolvedPatternVar,
 
   /// Resolve type of `nil` by providing a contextual type.
   SpecifyContextualTypeForNil,
@@ -2746,10 +2746,10 @@ class IgnoreInvalidASTNode final : public ConstraintFix {
   }
 };
 
-class IgnoreInvalidNamedPattern final : public ConstraintFix {
-  IgnoreInvalidNamedPattern(ConstraintSystem &cs, NamedPattern *pattern,
-                            ConstraintLocator *locator)
-      : ConstraintFix(cs, FixKind::IgnoreInvalidNamedPattern, locator) {}
+class IgnoreUnresolvedPatternVar final : public ConstraintFix {
+  IgnoreUnresolvedPatternVar(ConstraintSystem &cs, Pattern *pattern,
+                             ConstraintLocator *locator)
+      : ConstraintFix(cs, FixKind::IgnoreUnresolvedPatternVar, locator) {}
 
 public:
   std::string getName() const override {
@@ -2762,12 +2762,11 @@ class IgnoreInvalidNamedPattern final : public ConstraintFix {
     return diagnose(*commonFixes.front().first);
   }
 
-  static IgnoreInvalidNamedPattern *create(ConstraintSystem &cs,
-                                           NamedPattern *pattern,
-                                           ConstraintLocator *locator);
+  static IgnoreUnresolvedPatternVar *
+  create(ConstraintSystem &cs, Pattern *pattern, ConstraintLocator *locator);
 
   static bool classof(ConstraintFix *fix) {
-    return fix->getKind() == FixKind::IgnoreInvalidNamedPattern;
+    return fix->getKind() == FixKind::IgnoreUnresolvedPatternVar;
   }
 };
 

lib/Sema/CSBindings.cpp

@@ -115,7 +115,7 @@ bool BindingSet::isDelayed() const {
     // allows us to produce more specific errors because the type variable in
     // the expression that introduced the placeholder might be diagnosable using
     // fixForHole.
-    if (locator->isLastElement<LocatorPathElt::NamedPatternDecl>()) {
+    if (locator->isLastElement<LocatorPathElt::PatternDecl>()) {
       return true;
     }
 
@@ -1989,16 +1989,16 @@ TypeVariableBinding::fixForHole(ConstraintSystem &cs) const {
     return std::make_pair(fix, /*impact=*/(unsigned)10);
   }
 
-  if (auto pattern = getAsPattern<NamedPattern>(dstLocator->getAnchor())) {
+  if (auto pattern = getAsPattern(dstLocator->getAnchor())) {
     if (dstLocator->getPath().size() == 1 &&
-        dstLocator->isLastElement<LocatorPathElt::NamedPatternDecl>()) {
+        dstLocator->isLastElement<LocatorPathElt::PatternDecl>()) {
       // Not being able to infer the type of a variable in a pattern binding
       // decl is more dramatic than anything that could happen inside the
       // expression because we want to preferrably point the diagnostic to a
       // part of the expression that caused us to be unable to infer the
       // variable's type.
       ConstraintFix *fix =
-          IgnoreInvalidNamedPattern::create(cs, pattern, dstLocator);
+          IgnoreUnresolvedPatternVar::create(cs, pattern, dstLocator);
       return std::make_pair(fix, /*impact=*/(unsigned)100);
     }
   }

lib/Sema/CSFix.cpp

@@ -2004,18 +2004,18 @@ IgnoreResultBuilderWithReturnStmts::create(ConstraintSystem &cs, Type builderTy,
       IgnoreResultBuilderWithReturnStmts(cs, builderTy, locator);
 }
 
-bool IgnoreInvalidNamedPattern::diagnose(const Solution &solution,
-                                         bool asNote) const {
+bool IgnoreUnresolvedPatternVar::diagnose(const Solution &solution,
+                                          bool asNote) const {
   // Not being able to infer the type of a pattern should already have been
   // diagnosed on the pattern's initializer or as a structural issue of the AST.
   return true;
 }
 
-IgnoreInvalidNamedPattern *
-IgnoreInvalidNamedPattern::create(ConstraintSystem &cs, NamedPattern *pattern,
-                                  ConstraintLocator *locator) {
+IgnoreUnresolvedPatternVar *
+IgnoreUnresolvedPatternVar::create(ConstraintSystem &cs, Pattern *pattern,
+                                   ConstraintLocator *locator) {
   return new (cs.getAllocator())
-      IgnoreInvalidNamedPattern(cs, pattern, locator);
+      IgnoreUnresolvedPatternVar(cs, pattern, locator);
 }
 
 bool SpecifyBaseTypeForOptionalUnresolvedMember::diagnose(

lib/Sema/CSSimplify.cpp

@@ -12961,7 +12961,7 @@ ConstraintSystem::SolutionKind ConstraintSystem::simplifyFixConstraint(
   case FixKind::IgnoreInvalidASTNode: {
     return recordFix(fix, 10) ? SolutionKind::Error : SolutionKind::Solved;
   }
-  case FixKind::IgnoreInvalidNamedPattern: {
+  case FixKind::IgnoreUnresolvedPatternVar: {
     return recordFix(fix, 100) ? SolutionKind::Error : SolutionKind::Solved;
   }