coverage: Use `SpanMarker` to mark the full condition of `if !`

When MIR is built for an if-not expression, the `!` part of the condition
doesn't correspond to any MIR statement, so coverage instrumentation normally
can't see it.

We can fix that by deliberately injecting a dummy statement whose sole purpose
is to associate that span with its enclosing block.

5 files changed, 17 insertions, 12 deletions

diff --git a/compiler/rustc_mir_build/src/build/matches/mod.rs b/compiler/rustc_mir_build/src/build/matches/mod.rs
index 90f950d59d5..541b87af797 100644
--- a/compiler/rustc_mir_build/src/build/matches/mod.rs
+++ b/compiler/rustc_mir_build/src/build/matches/mod.rs
@@ -90,6 +90,11 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 let local_scope = this.local_scope();
                 let (success_block, failure_block) =
                     this.in_if_then_scope(local_scope, expr_span, |this| {
+                        // Help out coverage instrumentation by injecting a dummy statement with
+                        // the original condition's span (including `!`). This fixes #115468.
+                        if this.tcx.sess.instrument_coverage() {
+                            this.cfg.push_coverage_span_marker(block, this.source_info(expr_span));
+                        }
                         this.then_else_break(
                             block,
                             &this.thir[arg],
diff --git a/tests/coverage/if_not.cov-map b/tests/coverage/if_not.cov-map
index 73627308516..fb893e37960 100644
--- a/tests/coverage/if_not.cov-map
+++ b/tests/coverage/if_not.cov-map
@@ -1,5 +1,5 @@
 Function name: if_not::if_not
-Raw bytes (86): 0x[01, 01, 10, 01, 05, 05, 02, 3f, 09, 05, 02, 09, 3a, 3f, 09, 05, 02, 37, 0d, 09, 3a, 3f, 09, 05, 02, 0d, 32, 37, 0d, 09, 3a, 3f, 09, 05, 02, 0a, 01, 04, 01, 03, 0d, 02, 04, 05, 02, 06, 05, 02, 06, 00, 07, 3f, 04, 09, 00, 0d, 3a, 01, 05, 02, 06, 09, 02, 06, 00, 07, 37, 04, 09, 00, 0d, 32, 01, 05, 02, 06, 0d, 02, 0c, 02, 06, 2f, 03, 01, 00, 02]
+Raw bytes (86): 0x[01, 01, 10, 01, 05, 05, 02, 3f, 09, 05, 02, 09, 3a, 3f, 09, 05, 02, 37, 0d, 09, 3a, 3f, 09, 05, 02, 0d, 32, 37, 0d, 09, 3a, 3f, 09, 05, 02, 0a, 01, 04, 01, 03, 0d, 02, 04, 05, 02, 06, 05, 02, 06, 00, 07, 3f, 03, 09, 01, 0d, 3a, 02, 05, 02, 06, 09, 02, 06, 00, 07, 37, 03, 09, 01, 0d, 32, 02, 05, 02, 06, 0d, 02, 0c, 02, 06, 2f, 03, 01, 00, 02]
 Number of files: 1
 - file 0 => global file 1
 Number of expressions: 16
@@ -24,14 +24,14 @@ Number of file 0 mappings: 10
 - Code(Expression(0, Sub)) at (prev + 4, 5) to (start + 2, 6)
     = (c0 - c1)
 - Code(Counter(1)) at (prev + 2, 6) to (start + 0, 7)
-- Code(Expression(15, Add)) at (prev + 4, 9) to (start + 0, 13)
+- Code(Expression(15, Add)) at (prev + 3, 9) to (start + 1, 13)
     = (c1 + (c0 - c1))
-- Code(Expression(14, Sub)) at (prev + 1, 5) to (start + 2, 6)
+- Code(Expression(14, Sub)) at (prev + 2, 5) to (start + 2, 6)
     = ((c1 + (c0 - c1)) - c2)
 - Code(Counter(2)) at (prev + 2, 6) to (start + 0, 7)
-- Code(Expression(13, Add)) at (prev + 4, 9) to (start + 0, 13)
+- Code(Expression(13, Add)) at (prev + 3, 9) to (start + 1, 13)
     = (c2 + ((c1 + (c0 - c1)) - c2))
-- Code(Expression(12, Sub)) at (prev + 1, 5) to (start + 2, 6)
+- Code(Expression(12, Sub)) at (prev + 2, 5) to (start + 2, 6)
     = ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)
 - Code(Counter(3)) at (prev + 2, 12) to (start + 2, 6)
 - Code(Expression(11, Add)) at (prev + 3, 1) to (start + 0, 2)
diff --git a/tests/coverage/if_not.coverage b/tests/coverage/if_not.coverage
index 4c8ef9a84e2..41838b8513f 100644
--- a/tests/coverage/if_not.coverage
+++ b/tests/coverage/if_not.coverage
@@ -10,14 +10,14 @@
    LL|      8|    }
    LL|       |
    LL|       |    if
-   LL|       |        !
+   LL|     12|        !
    LL|     12|        cond
    LL|      4|    {
    LL|      4|        println!("cond was false");
    LL|      8|    }
    LL|       |
    LL|       |    if
-   LL|       |        !
+   LL|     12|        !
    LL|     12|        cond
    LL|      4|    {
    LL|      4|        println!("cond was false");
diff --git a/tests/coverage/lazy_boolean.cov-map b/tests/coverage/lazy_boolean.cov-map
index 0ad393c40fa..2d1ff24e62d 100644
--- a/tests/coverage/lazy_boolean.cov-map
+++ b/tests/coverage/lazy_boolean.cov-map
@@ -1,5 +1,5 @@
 Function name: lazy_boolean::main
-Raw bytes (636): 0x[01, 01, a4, 01, 01, 05, 09, 8a, 05, 8f, 05, 09, 05, 02, 05, 02, 8f, 05, 09, 05, 02, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 09, 8a, 05, 8f, 05, 09, 05, 02, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 19, ea, 04, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, e7, 04, 1d, 19, ea, 04, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 1d, e2, 04, e7, 04, 1d, 19, ea, 04, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, df, 04, 21, 1d, e2, 04, e7, 04, 1d, 19, ea, 04, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 21, da, 04, df, 04, 21, 1d, e2, 04, e7, 04, 1d, 19, ea, 04, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, d7, 04, 25, 21, da, 04, df, 04, 21, 1d, e2, 04, e7, 04, 1d, 19, ea, 04, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 25, d2, 04, d7, 04, 25, 21, da, 04, df, 04, 21, 1d, e2, 04, e7, 04, 1d, 19, ea, 04, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 1c, 01, 03, 01, 07, 0f, 05, 07, 10, 04, 06, 02, 04, 06, 00, 07, 87, 05, 02, 09, 00, 11, 8f, 05, 02, 0d, 00, 12, 8a, 05, 02, 0d, 00, 12, ff, 04, 03, 09, 00, 11, 87, 05, 02, 0d, 00, 12, 82, 05, 02, 0d, 00, 12, f7, 04, 02, 09, 00, 11, ff, 04, 00, 14, 00, 19, 11, 00, 1d, 00, 22, ef, 04, 01, 09, 00, 11, f7, 04, 00, 14, 00, 19, 15, 00, 1d, 00, 22, ef, 04, 04, 09, 00, 10, ea, 04, 01, 05, 03, 06, 19, 03, 06, 00, 07, e7, 04, 03, 09, 00, 10, 1d, 01, 05, 03, 06, e2, 04, 05, 05, 03, 06, df, 04, 05, 09, 00, 10, da, 04, 00, 11, 02, 06, 21, 02, 06, 00, 07, d7, 04, 02, 08, 00, 0f, 25, 00, 10, 02, 06, d2, 04, 02, 0c, 02, 06, cf, 04, 03, 01, 00, 02]
+Raw bytes (636): 0x[01, 01, a4, 01, 01, 05, 09, 8a, 05, 8f, 05, 09, 05, 02, 05, 02, 8f, 05, 09, 05, 02, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 09, 8a, 05, 8f, 05, 09, 05, 02, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 19, ea, 04, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, e7, 04, 1d, 19, ea, 04, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 1d, e2, 04, e7, 04, 1d, 19, ea, 04, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, df, 04, 21, 1d, e2, 04, e7, 04, 1d, 19, ea, 04, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 21, da, 04, df, 04, 21, 1d, e2, 04, e7, 04, 1d, 19, ea, 04, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, d7, 04, 25, 21, da, 04, df, 04, 21, 1d, e2, 04, e7, 04, 1d, 19, ea, 04, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 25, d2, 04, d7, 04, 25, 21, da, 04, df, 04, 21, 1d, e2, 04, e7, 04, 1d, 19, ea, 04, ef, 04, 19, 15, f2, 04, f7, 04, 15, 11, fa, 04, ff, 04, 11, 0d, 82, 05, 87, 05, 0d, 09, 8a, 05, 8f, 05, 09, 05, 02, 1c, 01, 03, 01, 07, 0f, 05, 07, 10, 04, 06, 02, 04, 06, 00, 07, 87, 05, 02, 09, 00, 11, 8f, 05, 02, 0d, 00, 12, 8a, 05, 02, 0d, 00, 12, ff, 04, 03, 09, 00, 11, 87, 05, 02, 0d, 00, 12, 82, 05, 02, 0d, 00, 12, f7, 04, 02, 09, 00, 11, ff, 04, 00, 14, 00, 19, 11, 00, 1d, 00, 22, ef, 04, 01, 09, 00, 11, f7, 04, 00, 14, 00, 19, 15, 00, 1d, 00, 22, ef, 04, 03, 09, 01, 10, ea, 04, 02, 05, 03, 06, 19, 03, 06, 00, 07, e7, 04, 03, 09, 00, 10, 1d, 01, 05, 03, 06, e2, 04, 05, 05, 03, 06, df, 04, 05, 08, 00, 10, da, 04, 00, 11, 02, 06, 21, 02, 06, 00, 07, d7, 04, 02, 08, 00, 0f, 25, 00, 10, 02, 06, d2, 04, 02, 0c, 02, 06, cf, 04, 03, 01, 00, 02]
 Number of files: 1
 - file 0 => global file 1
 Number of expressions: 164
@@ -194,9 +194,9 @@ Number of file 0 mappings: 28
 - Code(Expression(157, Add)) at (prev + 0, 20) to (start + 0, 25)
     = (c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4))
 - Code(Counter(5)) at (prev + 0, 29) to (start + 0, 34)
-- Code(Expression(155, Add)) at (prev + 4, 9) to (start + 0, 16)
+- Code(Expression(155, Add)) at (prev + 3, 9) to (start + 1, 16)
     = (c5 + ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) - c5))
-- Code(Expression(154, Sub)) at (prev + 1, 5) to (start + 3, 6)
+- Code(Expression(154, Sub)) at (prev + 2, 5) to (start + 3, 6)
     = ((c5 + ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) - c5)) - c6)
 - Code(Counter(6)) at (prev + 3, 6) to (start + 0, 7)
 - Code(Expression(153, Add)) at (prev + 3, 9) to (start + 0, 16)
@@ -204,7 +204,7 @@ Number of file 0 mappings: 28
 - Code(Counter(7)) at (prev + 1, 5) to (start + 3, 6)
 - Code(Expression(152, Sub)) at (prev + 5, 5) to (start + 3, 6)
     = ((c6 + ((c5 + ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) - c5)) - c6)) - c7)
-- Code(Expression(151, Add)) at (prev + 5, 9) to (start + 0, 16)
+- Code(Expression(151, Add)) at (prev + 5, 8) to (start + 0, 16)
     = (c7 + ((c6 + ((c5 + ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) - c5)) - c6)) - c7))
 - Code(Expression(150, Sub)) at (prev + 0, 17) to (start + 2, 6)
     = ((c7 + ((c6 + ((c5 + ((c4 + ((c3 + ((c2 + ((c1 + (c0 - c1)) - c2)) - c3)) - c4)) - c5)) - c6)) - c7)) - c8)
diff --git a/tests/coverage/lazy_boolean.coverage b/tests/coverage/lazy_boolean.coverage
index 8f14082ef68..2d927a08356 100644
--- a/tests/coverage/lazy_boolean.coverage
+++ b/tests/coverage/lazy_boolean.coverage
@@ -32,7 +32,7 @@
                                           ^0
    LL|       |
    LL|       |    if
-   LL|       |        !
+   LL|      1|        !
    LL|      1|        is_true
    LL|      0|    {
    LL|      0|        a = 2