title: Dockerfile build image fail
body: <p>Project Structure:</p>
  <pre><code>Syslog.Sample
  --docker.Sample
  --Syslog.Sample
  </code></pre>
  <p>Project &quot;docker.Sample&quot; -&gt; Add Docker support. This is the content of the generated Dockerfile:</p>
  <pre><code>FROM mcr.microsoft.com/dotnet/core/runtime:3.1-buster-slim AS base
  WORKDIR /app
  
  FROM mcr.microsoft.com/dotnet/core/sdk:3.1-buster AS build
  WORKDIR /src
  COPY [&quot;docker.Sample/docker.Sample.csproj&quot;, &quot;docker.Sample/&quot;]
  RUN dotnet restore &quot;docker.Sample/docker.Sample.csproj&quot;
  COPY . .
  WORKDIR &quot;/src/docker.Sample&quot;
  RUN dotnet build &quot;docker.Sample.csproj&quot; -c Release -o /app/build
  
  FROM build AS publish
  RUN dotnet publish &quot;docker.Sample.csproj&quot; -c Release -o /app/publish
  
  FROM base AS final
  WORKDIR /app
  COPY --from=publish /app/publish .
  ENTRYPOINT [&quot;dotnet&quot;, &quot;docker.Sample.dll&quot;]
  </code></pre>
  <p>Run command &quot;docker build .&quot;</p>
  <p>output fail context message:</p>
  <pre><code>failed to solve with frontend dockerfile.v0: failed to build LLB: failed to compute cache key: &quot;/docker.Sample/docker.Sample.csproj&quot; not found: not found
  </code></pre>
  <p>help me</p>