CI: Improve annotations (#1584)

* CI: Only run rustfmt in one environment

- This displays clippy warnings even when rustfmt fails.
- This avoids displaying 3 copies of the same rustfmt warning as Github
  annotations.
- Avoids duplicated work.

* CI: Suppress warnings when building for the oldest toolchain version

We had cases of warnings emitted due to `rustc` bugs that were fixed
in non-obsolete versions.

* factor: Remove a workaround for warnings on obsolete rustc

.github/workflows/CICD.yml

@@ -20,6 +20,47 @@ jobs:
   style:
     name: Style
     runs-on: ${{ matrix.job.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        job:
+          - { os: ubuntu-latest   , features: unix }
+    steps:
+    - uses: actions/checkout@v1
+    - name: Initialize workflow variables
+      id: vars
+      shell: bash
+      run: |
+        ## VARs setup
+        # target-specific options
+        # * CARGO_FEATURES_OPTION
+        CARGO_FEATURES_OPTION='' ;
+        if [ -n "${{ matrix.job.features }}" ]; then CARGO_FEATURES_OPTION='--features "${{ matrix.job.features }}"' ; fi
+        echo set-output name=CARGO_FEATURES_OPTION::${CARGO_FEATURES_OPTION}
+        echo ::set-output name=CARGO_FEATURES_OPTION::${CARGO_FEATURES_OPTION}
+    - name: Install `rust` toolchain
+      uses: actions-rs/toolchain@v1
+      with:
+        toolchain: stable
+        default: true
+        profile: minimal # minimal component installation (ie, no documentation)
+        components: rustfmt
+    - name: "`fmt` testing"
+      shell: bash
+      run: |
+        # `fmt` testing
+        # * convert any warnings to GHA UI annotations; ref: <https://help.github.com/en/actions/reference/workflow-commands-for-github-actions#setting-a-warning-message>
+        S=$(cargo fmt -- --check) && printf "%s\n" "$S" || { printf "%s\n" "$S" | sed -E -n -e "s/^Diff[[:space:]]+in[[:space:]]+${PWD//\//\\/}\/(.*)[[:space:]]+at[[:space:]]+[^0-9]+([0-9]+).*$/::warning file=\1,line=\2::WARNING: \`cargo fmt\`: style violation/p" ; }
+    - name: "`fmt` testing of tests"
+      shell: bash
+      run: |
+        # `fmt` testing of tests
+        # * convert any warnings to GHA UI annotations; ref: <https://help.github.com/en/actions/reference/workflow-commands-for-github-actions#setting-a-warning-message>
+        S=$(find tests -name "*.rs" -print0 | xargs -0 cargo fmt -- --check) && printf "%s\n" "$S" || { printf "%s\n" "$S" | sed -E -n "s/^Diff[[:space:]]+in[[:space:]]+${PWD//\//\\/}\/(.*)[[:space:]]+at[[:space:]]+[^0-9]+([0-9]+).*$/::warning file=\1,line=\2::WARNING: \`cargo fmt\`: style violation/p" ; }
+
+  clippy:
+    name: Clippy
+    runs-on: ${{ matrix.job.os }}
     strategy:
       fail-fast: false
       matrix:
@@ -46,19 +87,7 @@ jobs:
         toolchain: stable
         default: true
         profile: minimal # minimal component installation (ie, no documentation)
-        components: rustfmt, clippy
-    - name: "`fmt` testing"
-      shell: bash
-      run: |
-        # `fmt` testing
-        # * convert any warnings to GHA UI annotations; ref: <https://help.github.com/en/actions/reference/workflow-commands-for-github-actions#setting-a-warning-message>
-        S=$(cargo fmt -- --check) && printf "%s\n" "$S" || { printf "%s\n" "$S" | sed -E -n -e "s/^Diff[[:space:]]+in[[:space:]]+${PWD//\//\\/}\/(.*)[[:space:]]+at[[:space:]]+[^0-9]+([0-9]+).*$/::warning file=\1,line=\2::WARNING: \`cargo fmt\`: style violation/p" ; }
-    - name: "`fmt` testing of tests"
-      shell: bash
-      run: |
-        # `fmt` testing of tests
-        # * convert any warnings to GHA UI annotations; ref: <https://help.github.com/en/actions/reference/workflow-commands-for-github-actions#setting-a-warning-message>
-        S=$(find tests -name "*.rs" -print0 | xargs -0 cargo fmt -- --check) && printf "%s\n" "$S" || { printf "%s\n" "$S" | sed -E -n "s/^Diff[[:space:]]+in[[:space:]]+${PWD//\//\\/}\/(.*)[[:space:]]+at[[:space:]]+[^0-9]+([0-9]+).*$/::warning file=\1,line=\2::WARNING: \`cargo fmt\`: style violation/p" ; }
+        components: clippy
     - name: "`clippy` testing"
       if: success() || failure() # run regardless of prior step success/failure
       shell: bash
@@ -115,6 +144,8 @@ jobs:
       with:
         command: test
         args: --features "feat_os_unix"
+      env:
+        RUSTFLAGS: '-Awarnings'
 
   build:
     name: Build

src/uu/factor/src/numeric/mod.rs

@@ -9,6 +9,7 @@ mod gcd;
 pub use gcd::gcd;
 
 pub(crate) mod traits;
+use traits::{DoubleInt, Int, OverflowingAdd};
 
 mod modular_inverse;
 pub(crate) use modular_inverse::modular_inverse;

src/uu/factor/src/numeric/montgomery.rs

@@ -6,7 +6,6 @@
 // * For the full copyright and license information, please view the LICENSE file
 // * that was distributed with this source code.
 
-use super::traits::{DoubleInt, Int, OverflowingAdd};
 use super::*;
 use num_traits::identities::{One, Zero};