[AST] Handle a few more cases in getStartLoc()

Handle PatternBindingDecls with missing var locations, which can
happen for loop iterator vars, and FuncDecls with missing name and
func locations, which can happen for `defer`. Also while here make
sure we set the source location of a parser-produced ErrorExpr.

Author: hamishknight

include/swift/AST/Decl.h

@@ -2523,9 +2523,7 @@ class PatternBindingDecl final : public Decl,
                                                Pattern *Pat, Expr *E,
                                                DeclContext *Parent);
 
-  SourceLoc getStartLoc() const {
-    return StaticLoc.isValid() ? StaticLoc : VarLoc;
-  }
+  SourceLoc getStartLoc() const;
   SourceRange getSourceRange() const;
 
   unsigned getNumPatternEntries() const {
@@ -8413,9 +8411,7 @@ class FuncDecl : public AbstractFunctionDecl {
   SourceLoc getStaticLoc() const { return StaticLoc; }
   SourceLoc getFuncLoc() const { return FuncLoc; }
 
-  SourceLoc getStartLoc() const {
-    return StaticLoc.isValid() ? StaticLoc : FuncLoc;
-  }
+  SourceLoc getStartLoc() const;
   SourceRange getSourceRange() const;
 
   TypeRepr *getResultTypeRepr() const { return FnRetType.getTypeRepr(); }

lib/AST/Decl.cpp

@@ -2528,6 +2528,19 @@ StringRef PatternBindingEntry::getInitStringRepresentation(
   return extractInlinableText(ctx, init, scratch);
 }
 
+SourceLoc PatternBindingDecl::getStartLoc() const {
+  if (StaticLoc.isValid())
+    return StaticLoc;
+
+  if (VarLoc.isValid())
+    return VarLoc;
+
+  if (getPatternList().empty())
+    return SourceLoc();
+
+  return getPatternList().front().getStartLoc();
+}
+
 SourceRange PatternBindingDecl::getSourceRange() const {
   SourceLoc startLoc = getStartLoc();
   SourceLoc endLoc = getPatternList().empty()
@@ -11444,6 +11457,24 @@ DestructorDecl *DestructorDecl::getSuperDeinit() const {
   return nullptr;
 }
 
+SourceLoc FuncDecl::getStartLoc() const {
+  auto startLoc = StaticLoc;
+  if (startLoc.isInvalid())
+    startLoc = FuncLoc;
+  if (startLoc.isInvalid())
+    startLoc = getNameLoc();
+  if (startLoc.isInvalid())
+    startLoc = getSignatureSourceRange().Start;
+  if (startLoc.isInvalid())
+    startLoc = getResultTypeSourceRange().Start;
+  if (startLoc.isInvalid())
+    startLoc = getGenericTrailingWhereClauseSourceRange().Start;
+  if (startLoc.isInvalid())
+    startLoc = getOriginalBodySourceRange().Start;
+
+  return startLoc;
+}
+
 SourceRange FuncDecl::getSourceRange() const {
   SourceLoc startLoc = getStartLoc();
 

lib/Parse/ParseExpr.cpp

@@ -3639,7 +3639,7 @@ Parser::parseExprCollectionElement(std::optional<bool> &isDictionary) {
   } else {
     diagnose(Tok, diag::expected_colon_in_dictionary_literal);
     Value = makeParserResult(makeParserError(),
-                             new (Context) ErrorExpr(SourceRange()));
+                             new (Context) ErrorExpr(PreviousLoc));
   }
 
   // Make a tuple of Key Value pair.

test/Concurrency/async_main_resolution.swift

@@ -63,11 +63,11 @@ extension MainProtocol {
 #endif
 
 // CHECK-IS-SYNC-LABEL: "MyMain" interface_type="MyMain.Type"
-// CHECK-IS-SYNC: (func_decl {{.*}}implicit "$main()" interface_type="(MyMain.Type) -> () -> ()"
+// CHECK-IS-SYNC: (func_decl {{.*}}implicit range={{.*}} "$main()" interface_type="(MyMain.Type) -> () -> ()"
 // CHECK-IS-SYNC:       (declref_expr implicit type="(MyMain.Type) -> () -> ()"
 
 // CHECK-IS-ASYNC-LABEL: "MyMain" interface_type="MyMain.Type"
-// CHECK-IS-ASYNC: (func_decl {{.*}}implicit "$main()" interface_type="(MyMain.Type) -> () async -> ()"
+// CHECK-IS-ASYNC: (func_decl {{.*}}implicit range={{.*}} "$main()" interface_type="(MyMain.Type) -> () async -> ()"
 // CHECK-IS-ASYNC:       (declref_expr implicit type="(MyMain.Type) -> () async -> ()"
 
 // CHECK-IS-ERROR1: error: 'MyMain' is annotated with '@main' and must provide a main static function of type {{\(\) -> Void or \(\) throws -> Void|\(\) -> Void, \(\) throws -> Void, \(\) async -> Void, or \(\) async throws -> Void}}

test/Concurrency/where_clause_main_resolution.swift

@@ -25,19 +25,19 @@ protocol App {
 // CHECK-SAME: interface_type="<Self where Self : App> (Self.Type) -> () async -> ()"
 
 extension App where Configuration == Config1 {
-// CHECK-CONFIG1: (func_decl {{.*}}implicit "$main()" interface_type="(MainType.Type) -> () -> ()"
+// CHECK-CONFIG1: (func_decl {{.*}}implicit range=[{{.*}}:[[@LINE+20]]:1 - line:[[@LINE+20]]:1] "$main()" interface_type="(MainType.Type) -> () -> ()"
 // CHECK-CONFIG1: [[SOURCE_FILE]]:[[# @LINE+1 ]]
     static func main() { }
 }
 
 extension App where Configuration == Config2 {
-// CHECK-CONFIG2: (func_decl {{.*}}implicit "$main()" interface_type="(MainType.Type) -> () async -> ()"
+// CHECK-CONFIG2: (func_decl {{.*}}implicit range=[{{.*}}:[[@LINE+14]]:1 - line:[[@LINE+14]]:1] "$main()" interface_type="(MainType.Type) -> () async -> ()"
 // CHECK-CONFIG2: [[SOURCE_FILE]]:[[# @LINE+1 ]]
     static func main() async { }
 }
 
 extension App where Configuration == Config3 {
-// CHECK-CONFIG3-ASYNC: (func_decl {{.*}}implicit "$main()" interface_type="(MainType.Type) -> () async -> ()"
+// CHECK-CONFIG3-ASYNC: (func_decl {{.*}}implicit range=[{{.*}}:[[@LINE+8]]:1 - line:[[@LINE+8]]:1] "$main()" interface_type="(MainType.Type) -> () async -> ()"
 // CHECK-CONFIG3-ASYNC: [[SOURCE_FILE]]:[[DEFAULT_ASYNCHRONOUS_MAIN_LINE]]
 }
 

test/attr/ApplicationMain/attr_main_throws.swift

@@ -7,7 +7,7 @@ struct MyBase {
   }
 }
 
-// CHECK-AST: (func_decl {{.*}} implicit "$main()" interface_type="(MyBase.Type) -> () throws -> ()" access=internal static
+// CHECK-AST: (func_decl {{.*}} implicit range=[{{.*}}:[[@LINE-6]]:1 - line:[[@LINE-6]]:1] "$main()" interface_type="(MyBase.Type) -> () throws -> ()" access=internal static
 // CHECK-AST-NEXT:  (parameter "self" {{.*}})
 // CHECK-AST-NEXT:  (parameter_list)
 // CHECK-AST-NEXT:  (brace_stmt implicit

test/expr/capture/top-level-guard.swift

@@ -39,7 +39,7 @@ let closureCapture: () -> Void = { [x] in
 }
 
 // CHECK-LABEL: (defer_stmt
-// CHECK-NEXT: (func_decl{{.*}}implicit "$defer()" interface_type="() -> ()" access=fileprivate captures=(x<direct><noescape>)
+// CHECK-NEXT: (func_decl{{.*}}implicit range={{.*}} "$defer()" interface_type="() -> ()" access=fileprivate captures=(x<direct><noescape>)
 defer {
   _ = x
 }