[core] Fix modernize-return-braced-init-list errors

As reported by clang-tidy-8.

9 files changed, 35 insertions, 47 deletions

diff --git a/platform/default/src/mbgl/storage/online_file_source.cpp b/platform/default/src/mbgl/storage/online_file_source.cpp
index 6dc4de0ac7..e72b506118 100644
--- a/platform/default/src/mbgl/storage/online_file_source.cpp
+++ b/platform/default/src/mbgl/storage/online_file_source.cpp
@@ -245,7 +245,7 @@ private:
 
         optional<OnlineFileRequest*> pop() {
             if (queue.empty()) {
-                return optional<OnlineFileRequest*>();
+                return {};
             }
 
             if (queue.begin() == firstLowPriorityRequest) {
@@ -254,7 +254,7 @@ private:
 
             OnlineFileRequest* next = queue.front();
             queue.pop_front();
-            return optional<OnlineFileRequest*>(next);
+            return {next};
         }
 
         bool contains(OnlineFileRequest* request) const {
diff --git a/src/mbgl/geometry/line_atlas.cpp b/src/mbgl/geometry/line_atlas.cpp
index 656cfbd25c..6ddf16af0b 100644
--- a/src/mbgl/geometry/line_atlas.cpp
+++ b/src/mbgl/geometry/line_atlas.cpp
@@ -140,7 +140,7 @@ LinePatternPos addDashPattern(AlphaImage& image,
 
     if (dasharray.size() < 2) {
         Log::Warning(Event::ParseStyle, "line dasharray requires at least two elements");
-        return LinePatternPos();
+        return {};
     }
 
     float length = 0;
diff --git a/src/mbgl/layout/symbol_projection.cpp b/src/mbgl/layout/symbol_projection.cpp
index 628caf6eca..eecaced824 100644
--- a/src/mbgl/layout/symbol_projection.cpp
+++ b/src/mbgl/layout/symbol_projection.cpp
@@ -242,19 +242,17 @@ namespace mbgl {
                                                             const bool returnTileDistance) {
         if (symbol.glyphOffsets.empty()) {
             assert(false);
-            return optional<std::pair<PlacedGlyph, PlacedGlyph>>();
+            return {};
         }
         
         const float firstGlyphOffset = symbol.glyphOffsets.front();
         const float lastGlyphOffset = symbol.glyphOffsets.back();;
 
         optional<PlacedGlyph> firstPlacedGlyph = placeGlyphAlongLine(fontScale * firstGlyphOffset, lineOffsetX, lineOffsetY, flip, anchorPoint, tileAnchorPoint, symbol.segment, symbol.line, symbol.tileDistances, labelPlaneMatrix,  returnTileDistance);
-        if (!firstPlacedGlyph)
-            return optional<std::pair<PlacedGlyph, PlacedGlyph>>();
+        if (!firstPlacedGlyph) return {};
 
         optional<PlacedGlyph> lastPlacedGlyph = placeGlyphAlongLine(fontScale * lastGlyphOffset, lineOffsetX, lineOffsetY, flip, anchorPoint, tileAnchorPoint, symbol.segment, symbol.line, symbol.tileDistances, labelPlaneMatrix, returnTileDistance);
-        if (!lastPlacedGlyph)
-            return optional<std::pair<PlacedGlyph, PlacedGlyph>>();
+        if (!lastPlacedGlyph) return {};
 
         return std::make_pair(*firstPlacedGlyph, *lastPlacedGlyph);
     }
diff --git a/src/mbgl/map/map.cpp b/src/mbgl/map/map.cpp
index eda16160ae..91a657294c 100644
--- a/src/mbgl/map/map.cpp
+++ b/src/mbgl/map/map.cpp
@@ -187,7 +187,7 @@ CameraOptions Map::cameraForLatLngBounds(const LatLngBounds& bounds,
 
 CameraOptions cameraForLatLngs(const std::vector<LatLng>& latLngs, const Transform& transform, const EdgeInsets& padding) {
     if (latLngs.empty()) {
-        return CameraOptions();
+        return {};
     }
     Size size = transform.getState().getSize();
     // Calculate the bounds of the possibly rotated shape with respect to the viewport.
diff --git a/src/mbgl/programs/symbol_program.cpp b/src/mbgl/programs/symbol_program.cpp
index 5e3e12a1f8..c4a86bb074 100644
--- a/src/mbgl/programs/symbol_program.cpp
+++ b/src/mbgl/programs/symbol_program.cpp
@@ -168,19 +168,18 @@ SymbolTextAndIconProgram::LayoutUniformValues SymbolTextAndIconProgram::layoutUn
     const TransformState& state,
     const float symbolFadeChange,
     const SymbolSDFPart part) {
-    return SymbolTextAndIconProgram::LayoutUniformValues(
-        SymbolSDFProgram<SymbolSDFTextProgram, style::TextPaintProperties>::layoutUniformValues(true,
-                                                                                                hasVariablePacement,
-                                                                                                values,
-                                                                                                texsize,
-                                                                                                pixelsToGLUnits,
-                                                                                                pixelRatio,
-                                                                                                alongLine,
-                                                                                                tile,
-                                                                                                state,
-                                                                                                symbolFadeChange,
-                                                                                                part)
-            .concat(gfx::UniformValues<SymbolTextAndIconProgramUniforms>(uniforms::texsize::Value(texsize_icon))));
+    return {SymbolSDFProgram<SymbolSDFTextProgram, style::TextPaintProperties>::layoutUniformValues(true,
+                                                                                                    hasVariablePacement,
+                                                                                                    values,
+                                                                                                    texsize,
+                                                                                                    pixelsToGLUnits,
+                                                                                                    pixelRatio,
+                                                                                                    alongLine,
+                                                                                                    tile,
+                                                                                                    state,
+                                                                                                    symbolFadeChange,
+                                                                                                    part)
+                .concat(gfx::UniformValues<SymbolTextAndIconProgramUniforms>(uniforms::texsize::Value(texsize_icon)))};
 }
 
 template class SymbolSDFProgram<SymbolSDFIconProgram, style::IconPaintProperties>;
diff --git a/src/mbgl/style/expression/coercion.cpp b/src/mbgl/style/expression/coercion.cpp
index d65558e28d..518d127720 100644
--- a/src/mbgl/style/expression/coercion.cpp
+++ b/src/mbgl/style/expression/coercion.cpp
@@ -25,7 +25,7 @@ EvaluationResult toNumber(const Value& v) {
             try {
                 return util::stof(s);
             } catch (...) {
-                return optional<double>();
+                return {};
             }
         },
         [](const auto&) { return optional<double>(); }
diff --git a/src/mbgl/style/expression/compound_expression.cpp b/src/mbgl/style/expression/compound_expression.cpp
index 30abe37d2e..45b8b793a2 100644
--- a/src/mbgl/style/expression/compound_expression.cpp
+++ b/src/mbgl/style/expression/compound_expression.cpp
@@ -246,12 +246,10 @@ optional<double> featurePropertyAsDouble(const EvaluationContext& params, const
     assert(params.feature);
     auto property = params.feature->getValue(key);
     if (!property) return {};
-    return property->match(
-        [](double value) { return value; },
-        [](uint64_t value) { return optional<double>(static_cast<double>(value)); },
-        [](int64_t value) { return optional<double>(static_cast<double>(value)); },
-        [](auto) { return optional<double>(); }
-    );
+    return property->match([](double value) { return value; },
+                           [](uint64_t value) -> optional<double> { return {static_cast<double>(value)}; },
+                           [](int64_t value) -> optional<double> { return {static_cast<double>(value)}; },
+                           [](auto) -> optional<double> { return {}; });
 };
 
 optional<std::string> featurePropertyAsString(const EvaluationContext& params, const std::string& key) {
@@ -267,12 +265,10 @@ optional<std::string> featurePropertyAsString(const EvaluationContext& params, c
 optional<double> featureIdAsDouble(const EvaluationContext& params) {
     assert(params.feature);
     auto id = params.feature->getID();
-    return id.match(
-        [](double value) { return value; },
-        [](uint64_t value) { return optional<double>(static_cast<double>(value)); },
-        [](int64_t value) { return optional<double>(static_cast<double>(value)); },
-        [](auto) { return optional<double>(); }
-    );
+    return id.match([](double value) { return value; },
+                    [](uint64_t value) -> optional<double> { return {static_cast<double>(value)}; },
+                    [](int64_t value) -> optional<double> { return {static_cast<double>(value)}; },
+                    [](auto) -> optional<double> { return {}; });
 };
 
 optional<std::string> featureIdAsString(const EvaluationContext& params) {
@@ -1160,10 +1156,8 @@ EvaluationResult CompoundExpression::evaluate(const EvaluationContext& evaluatio
 }
 
 optional<std::size_t> CompoundExpression::getParameterCount() const {
-    return signature.params.match(
-        [&](const VarargsType&) { return optional<std::size_t>(); },
-        [&](const std::vector<type::Type>& p) -> optional<std::size_t> { return p.size(); }
-    );
+    return signature.params.match([&](const VarargsType&) -> optional<std::size_t> { return {}; },
+                                  [&](const std::vector<type::Type>& p) -> optional<std::size_t> { return p.size(); });
 }
 
 std::vector<optional<Value>> CompoundExpression::possibleOutputs() const {
diff --git a/src/mbgl/style/property_expression.cpp b/src/mbgl/style/property_expression.cpp
index 8d603e4b15..290009514e 100644
--- a/src/mbgl/style/property_expression.cpp
+++ b/src/mbgl/style/property_expression.cpp
@@ -40,14 +40,11 @@ float PropertyExpressionBase::interpolationFactor(const Range<float>& inputLevel
 
 Range<float> PropertyExpressionBase::getCoveringStops(const float lower, const float upper) const noexcept {
     return zoomCurve.match(
-        [](std::nullptr_t) {
+        [](std::nullptr_t) -> Range<float> {
             assert(false);
-            return Range<float>(0.0f, 0.0f);
+            return {0.0f, 0.0f};
         },
-        [&](auto z) {
-            return z->getCoveringStops(lower, upper);
-        }
-    );
+        [&](auto z) { return z->getCoveringStops(lower, upper); });
 }
 
 const expression::Expression& PropertyExpressionBase::getExpression() const noexcept {
diff --git a/src/mbgl/text/shaping.cpp b/src/mbgl/text/shaping.cpp
index 725a93555b..b18033a40e 100644
--- a/src/mbgl/text/shaping.cpp
+++ b/src/mbgl/text/shaping.cpp
@@ -285,8 +285,8 @@ PotentialBreak evaluateBreak(const std::size_t breakIndex, const float breakX, c
             bestBreakBadness = breakBadness;
         }
     }
-    
-    return PotentialBreak(breakIndex, breakX, bestPriorBreak, bestBreakBadness);
+
+    return {breakIndex, breakX, bestPriorBreak, bestBreakBadness};
 }
 
 std::set<std::size_t> leastBadBreaks(const PotentialBreak& lastLineBreak) {