diff --git a/mlir/lib/Conversion/ShapeToStandard/ShapeToStandard.cpp b/mlir/lib/Conversion/ShapeToStandard/ShapeToStandard.cpp
--- a/mlir/lib/Conversion/ShapeToStandard/ShapeToStandard.cpp
+++ b/mlir/lib/Conversion/ShapeToStandard/ShapeToStandard.cpp
@@ -178,6 +178,10 @@
 LogicalResult
 RankOpConverter::matchAndRewrite(shape::RankOp op, ArrayRef<Value> operands,
                                  ConversionPatternRewriter &rewriter) const {
+  // For now, this lowering supports only error-free types.
+  if (op.getType().isa<SizeType>())
+    return failure();
+
   shape::RankOp::Adaptor transformed(operands);
   rewriter.replaceOpWithNewOp<DimOp>(op, transformed.shape(), 0);
   return success();
@@ -232,7 +236,7 @@
 
   // Apply conversion.
   auto module = getOperation();
-  if (failed(applyFullConversion(module, target, patterns)))
+  if (failed(applyPartialConversion(module, target, patterns)))
     signalPassFailure();
 }
 
diff --git a/mlir/test/Conversion/ShapeToStandard/shape-to-standard.mlir b/mlir/test/Conversion/ShapeToStandard/shape-to-standard.mlir
--- a/mlir/test/Conversion/ShapeToStandard/shape-to-standard.mlir
+++ b/mlir/test/Conversion/ShapeToStandard/shape-to-standard.mlir
@@ -84,6 +84,16 @@
 
 // -----
 
+// Don't lower `rank` if type is not error-free.
+// CHECK-LABEL: @rank
+func @rank(%shape : !shape.shape) {
+  // CHECK: shape.rank
+  %rank = shape.rank %shape : !shape.shape -> !shape.size
+  return
+}
+
+// -----
+
 // Express `get_extent` as `std.dim` when it relies directly on the outcome of a
 // `shape_of` operation.
 // CHECK-LABEL: @get_extent_shape_of