[SourceKit] In related identes, report underlying var of shorthand if let binding

Author: ahoppen

test/SourceKit/RelatedIdents/related_idents.swift

@@ -93,6 +93,18 @@ func closureCaptureWithExplicitName() {
   }
 }
 
+func shorthandIfLet(test: Int?) {
+  if let test {
+    print(test)
+  }
+}
+
+func ifLet(test: Int?) {
+  if let test = test {
+    print(test)
+  }
+}
+
 // RUN: %sourcekitd-test -req=related-idents -pos=6:17 %s -- -module-name related_idents %s | %FileCheck -check-prefix=CHECK1 %s
 // CHECK1: START RANGES
 // CHECK1-NEXT: 1:7 - 2
@@ -208,3 +220,26 @@ func closureCaptureWithExplicitName() {
 // CHECK14-NEXT: 91:20 - 4
 // CHECK14-NEXT: 92:11 - 4
 // CHECK14-NEXT: END RANGES
+
+// RUN: %sourcekitd-test -req=related-idents -pos=96:21 %s -- -module-name related_idents %s | %FileCheck -check-prefix=CHECK15 %s
+// RUN: %sourcekitd-test -req=related-idents -pos=97:10 %s -- -module-name related_idents %s | %FileCheck -check-prefix=CHECK15 %s
+// RUN: %sourcekitd-test -req=related-idents -pos=98:11 %s -- -module-name related_idents %s | %FileCheck -check-prefix=CHECK15 %s
+// CHECK15:      START RANGES
+// CHECK15-NEXT: 96:21 - 4
+// CHECK15-NEXT: 97:10 - 4
+// CHECK15-NEXT: 98:11 - 4
+// CHECK15-NEXT: END RANGES
+
+// RUN: %sourcekitd-test -req=related-idents -pos=102:12 %s -- -module-name related_idents %s | %FileCheck -check-prefix=CHECK16 %s
+// RUN: %sourcekitd-test -req=related-idents -pos=103:17 %s -- -module-name related_idents %s | %FileCheck -check-prefix=CHECK16 %s
+// CHECK16:      START RANGES
+// CHECK16-NEXT: 102:12 - 4
+// CHECK16-NEXT: 103:17 - 4
+// CHECK16-NEXT: END RANGES
+
+// RUN: %sourcekitd-test -req=related-idents -pos=103:10 %s -- -module-name related_idents %s | %FileCheck -check-prefix=CHECK17 %s
+// RUN: %sourcekitd-test -req=related-idents -pos=104:11 %s -- -module-name related_idents %s | %FileCheck -check-prefix=CHECK17 %s
+// CHECK17:      START RANGES
+// CHECK17-NEXT: 103:10 - 4
+// CHECK17-NEXT: 104:11 - 4
+// CHECK17-NEXT: END RANGES

tools/SourceKit/lib/SwiftLang/SwiftSourceDocInfo.cpp

@@ -2234,6 +2234,41 @@ class RelatedIdScanner : public SourceEntityWalker {
     return true;
   }
 
+  bool walkToStmtPre(Stmt *S) override {
+    if (Cancelled)
+      return false;
+
+    if (auto CondStmt = dyn_cast<LabeledConditionalStmt>(S)) {
+      for (const StmtConditionElement &Cond : CondStmt->getCond()) {
+        if (Cond.getKind() != StmtConditionElement::CK_PatternBinding) {
+          continue;
+        }
+        auto Init = dyn_cast<DeclRefExpr>(Cond.getInitializer());
+        if (!Init) {
+          continue;
+        }
+        auto ReferencedVar = dyn_cast_or_null<VarDecl>(Init->getDecl());
+        if (!ReferencedVar) {
+          continue;
+        }
+
+        Cond.getPattern()->forEachVariable([&](VarDecl *DeclaredVar) {
+          if (DeclaredVar->getLoc() != Init->getLoc()) {
+            return;
+          }
+          assert(DeclaredVar->getName() == ReferencedVar->getName());
+          if (DeclaredVar == Dcl) {
+            RelatedDecls.push_back(ReferencedVar);
+          }
+          if (ReferencedVar == Dcl) {
+            RelatedDecls.push_back(DeclaredVar);
+          }
+        });
+      }
+    }
+    return true;
+  }
+
   bool walkToDeclPre(Decl *D, CharSourceRange Range) override {
     if (Cancelled)
       return false;